Sustainable Workplace: Impact of Authentic Leadership on Change-Oriented Organizational Citizenship Behavior and the Moderating Role of Perceived Employees’ Calling

To be sustainable in the current rapidly changing business environment, organizations must strive to adapt and respond to a new environment. Employees are the key performers of organizational change. Furthermore, change-oriented organizational citizenship behavior (OCB) is essential for them to positively accept and implement organizational change. Additionally, the leader’s role is crucial to promoting such change-oriented OCB. In this regard, this study investigates the effect of authentic leadership on change-oriented OCB, demonstrating that the vocational calling of employees strengthens such positive influences. Based on the self-determination theory (SDT), this study examines that the moderating effect between authentic leadership on change-oriented OCB increases when employees have a higher perception of calling for work than lower. This study uses a two-wave data set gathered from 485 currently working employees in South Korea. The empirical analysis is revealed below. First, authentic leadership has a positive effect on direct OCB. Second, employees’ perception of calling has a positive effect on direct change-oriented OCB. Third, the higher the level of employees’ perception of calling, the greater the effect of authentic leadership on change-oriented OCB. The most significant theoretical contribution of the study is that it is the first to determine that calling acts as a moderating factor between authentic leadership and change-oriented OCB. The fact that the positive effect of authentic leadership on change-oriented OCB increases when there is a high calling implies that employees are more likely to conduct change-oriented OCB when they perceive a high level of calling. Based on this result, this study explains the method and reason for maximizing change-oriented OCB through authentic leadership.


Introduction
Business operations are currently facing complicated external environments as well as growing uncertainties. To adapt to such problems, organizations are required to identify the internal problems and ascertain the necessary coping procedures [1]. Frontline employees can better identify and solve such problems [2]. Further, Katz [3] emphasized the importance of "innovative and spontaneous behavior" for the continued success of an organization (p. 132). According to existing literature, the change-oriented organizational citizenship behavior (OCB, henceforth "OCB") of employees is an important element for organizations to adopt change and improve performance [4,5]. Change-oriented OCB includes the voluntary participation of employees in organizational change, such as detecting and correcting the organization's errors and making suggestions to improve work performance [4,6]. Therefore, change-oriented OCB is crucial in such environments, and managers must provide the context to encourage employees to participate in change-oriented OCB [7]. However, thus far very few studies are exploring the leader's influence on changeoriented OCB [7], while most are examining the effect of the more extensive leadership behavior theory on change-oriented OCB, such as leader-member exchange (LMX)(e.g., [1]) and leader support [4], or the change-oriented leadership theory (e.g., [8]). Despite the proposition that the understanding of the essence of change-oriented OCB can only be enhanced if researchers focus more on leadership as an antecedent [4,8], the research on leadership and change-oriented OCB is still insufficient.
It is important to understand the role of leadership perceived by the employees amidst such complicated and rapid changes [9]. It is further suggested that authentic leadership can contribute to the effect of change [10]. Authentic leadership is a new alternative to leadership that can help organizations overcome many difficulties in the face of changes. For this reason many studies are being conducted to develop authentic leadership as an independent leadership theory (authentic leadership theory; ALT) and the pursuit is still actively underway.
Specially, the need to consider the situational factors in studying authentic leadership is constantly being highlighted [11][12][13]. Thus, in response to the need, it is theoretically and practically important for firms to explore the effect of authentic leadership, which is an antecedent to change-oriented OCB, as well as the moderating variables in their relationship, in order to cope with the uncertainties of today's external environment for sustainable management.
This study expands the scope of previous studies and makes contributions in the following aspects. First, this study proposes theoretical models proving that authentic leadership positively influences change-oriented OCB. Previous studies had limited interest in new aspects of OCB initiatives [4,14,15], while very few studies examined the leader's influence on the change-oriented OCB of employees. For example, some studies examined transformational leadership [8], empowering leadership [7], participative leadership [16], and inclusive leadership [17] as antecedents of change-oriented OCB. However, authentic leadership, which is receiving more attention recently as the leader's authenticity is gaining more importance, may have a positive effect on change-oriented behavior of employees. Alavi and Gill [10] presented logical propositions and called for an empirical research on authentic leadership and change-oriented behavior of employees. Therefore, this study is the first to examine authentic leadership as an antecedent of change-oriented OCB.
Second, this study examines that employees' perception of calling positively influences change-oriented OCB. Calling has been studied in over 200 studies in the last 10 years; it is examined to positively influence job satisfaction and job performance [18]. Employees' calling in an organization is important as it is assigned intuitively and is consistent [19][20][21]. Also, some studies on employees in South Korea examine that an increase in job level may contribute to developing calling (e.g., [22]). In other words, calling is an ongoing process which cannot be abruptly influenced [23,24], which can be developed even if an individual is not born with it; therefore, it must be studied in the interest of sustainable management in the changing environment. Individuals with a calling seek the value of a selfless life [25]. Therefore, calling positively influences extra-role behavior or OCB [26,27]. However, thus far, no research has demonstrated the effect of calling on changeoriented OCB.
Third, this study examines calling as a new moderating variable between authentic leadership and change-oriented OCB. As previously mentioned, few studies have examined that authentic leadership positively influences change-oriented OCB. However, no studies have explored the moderating factors that can increase or decrease the effect of authentic leadership on change-oriented OCB. Accordingly, this study examines the positive moderating effect of calling, which increases the effect of authentic leadership on changeoriented OCB. Our study makes theoretical contributions and provides adequate guidelines for organizational practice.

Authentic Leadership
Authenticity is defined as the extent to which an individual is sincere to oneself and behaves accordingly by emphasizing their core values [28,29]. Further, considering its impact on the well-being and interpersonal relations of human beings, authenticity is an important topic in modern psychology [28][29][30]. Authenticity is the outcome of the mechanism for dynamic regulation [30]. Authentic leadership is a form of positive leadership in which one is aware of their strengths, weaknesses, and values based on authenticity and interacts with others with that knowledge [30]. The most commonly accepted form of authentic leadership is the four sub-dimensions in the measurement the Authentic Leadership Questionnaire (ALQ), presented by Walumbwa et al. [31]: self-awareness, balanced processing, relational transparency, and internalized moral perspective.
Self-awareness indicates that the leaders are well aware of themselves [32]. They can also understand how behavior displayed through self-awareness affects employees. Therefore, self-awareness affects the leader's thinking, motivation, and behavior. Further, authentic leaders with a high level of self-awareness are more capable of leading and developing the employees.
Balanced processing refers to objective thinking through both positive and negative aspects in problem solving. Leaders use open methods and highly relevant information to enable objective decision making. For example, leaders tend to closely analyze relevant facts before making important decisions and have employees participate in the decisionmaking process by seeking their diverse opinions and listening attentively. This characteristic of authentic leaders gives employees the impression that the leaders consider the opinions of the employees instead of simply imposing their own.
Relational transparency refers to behaving according to one's true nature instead of manipulated or fake behavior. Leaders with relational transparency honestly share all kinds of information including their genuine thoughts and emotions. They promote positive relationships by sincerely obtaining both consent and dissent from the employees. Authentic leaders that adopt this behavior induce openness, responsibility, and honesty between the leaders and employees [33], hence clarifying the expectations they have toward each other and consequently promoting mutual social exchange.
Finally, internalized moral perspective indicates that authentic leaders control themselves under a moral perspective and behave according to the norms [34]. They exhibit a high level of moral behavior relying on their internalized moral standards and values rather than on external social pressure. Therefore, authentic leaders consider matters ethically, from a broader and deeper perspective when they, the employees, or the organization face grave ethical issues [35].

Change-Oriented OCB
Change-oriented OCB is a concept that separates OCB in the individual initiative from the concept of OCB. Generally, OCB can be defined as a discretionary individual behavior, which overall promotes organizational performance but is excluded from the organization's formal reward system [36]. This behavior is considered the most desirable for organizational efficiency [37]. Previous studies have commonly classified OCB into various internal dimensions. For example, Organ [38] classified OCB into five dimensions: altruism, courtesy, conscientiousness, civic virtue, sportsmanship. Williams and Anderson [39] divided it into two aspects: citizenship behavior toward individuals and behavior toward organizations. Podsakoff et al. [36] further classified OCB into seven sub-factors: helping, sportsmanship, organizational loyalty, compliance, civic virtue, self-development, and initiative.
Evidently, the concept of change-oriented OCB was formed during its developing process in the aforementioned studies. In other words, the foundation is built upon the perception that an organization, for its survival, needs employees with an enterprising spirit who can bring forth constructive changes [6,40]. The study by Van Dyne and LePine [41] offers a look into the early conceptual research on change-oriented OCB. They strived to distinguish between in-role and extra-role behaviors, and from the latter, classified altruism and helping behavior of OCB as affiliative promotive behavior. Podsakoff et al. [36] later categorized OCB into seven sub-factors, but Choi [4] argued that some of the factors should consider further dimensions of OCB directed toward an organization. Choi [4] criticized that all types of OCB, with the exception of individual initiative, failed to break away from the affiliative promotive category, and proposed that only the concept of individual initiative is employed to prompt "voluntary acts of creativity and innovation designed to improve one's task or the organization's performance" (p. 24) in change-inducing behavior. This form of task performance has now come to be known as changeoriented OCB.
Change-oriented OCB is increasingly becoming important because, as the competition becomes more intense, the business environment becomes more unpredictable, and the employees must become more active, flexible, and innovative [6,42]. In other words, front-line employees must be able to identify their companies' problems and devise creative and innovative ways to perform their duties [1] for the current firms to be sustainable. Choi [4] supports this argument, claiming that having employees simply work hard in a harmonious environment is not enough to improve performance in a changing environment. Therefore, this study selected the change-oriented OCB of employees as a dependent variable, defining it as the effort put in voluntary acts of creativity and innovation for a positive change in methods, procedures, and systems designed to improve an employee's task or the organization's performance.

Authentic Leadership and Change-Oriented OCB
According to previous studies, employees under authentic leaders put more effort in their tasks, participate in more OCBs, and exhibit better work performance [31,[43][44][45]. However, for organizations to implement change initiative for sustainable success, innovative and voluntary change-oriented behavior among employees is necessary, which requires actions that support such behavior [46]. Change-oriented OCB requires a better understanding of the antecedents of OCB in the context of change [4]. Further, authentic leadership is a significant antecedent that induces change-oriented OCB among employees. Accordingly, change-oriented OCB can be an outcome of authentic leadership through commitment to change, which is something authentic leaders can inculcate among employees.
Meyer [47] further claimed that affective commitment may induce discretionary behavior and conceptualized discretionary behavior as additional effort toward the organization, similar to OCB. From this perspective, authentic leaders may also affect the change-oriented OCB of employees by intensifying their vision and values towards change [10]. Authentic leaders can transfer their internalized values to employees. Further, employees can learn from their leaders. The values of leaders can be internalized by this positive role modeling mechanism [45]. In other words, when the internalized values of authentic leaders are related to specific change, employees can have internalized values regarding change, hence affecting their change-oriented OCB [4].
Employees in an authentic relationship with their leaders can link their internalized values to the value of change. Considering that authentic leadership is a relational phenomenon [48], authentic employees can play an important role in the process of authentic leadership by interacting with authentic leaders, hence enabling the leaders and employees to know each other better and develop a more transparent and authentic relationship [43,45]. According to the LMX theory, the quality of LMX is an important antecedent to OCB in various studies [36]. Authentic leaders can create situations in which employees develop trust in their leaders, which is a component of LMX, based on authenticity [49]. This is further expected to develop a high level of LMX by building a transparent and authentic relationship between leaders and employees [50][51][52] and increasing the change-oriented OCB in these relationships. Based on the aforementioned logic and previous studies, we hypothesize that:

Calling
Humans are naturally meaning-seeking creatures [53]. Calling is defined as the way people perceive that their work is meaningful. Work is key in an individual's life. Therefore, the meaning that comes from work is an important research topic in organizational behavior [54]. Further, more researchers in organizational behavior are recently studying this topic with interest [23].
Initially, studies on calling used it as a religious term that encouraged individuals to work through a transcendental being. However, many researchers currently conceptualize it as a meaningful job (e.g., [18,19]). Therefore, it is defined as a goal-oriented attitude toward a job. In other words, calling is a belief that gives meaning to work and must be executed by oneself [55]. Further, calling has a significant meaning as a part rather than a means of one's life [56]. Consequently, people who feel a calling toward their jobs attach great importance and meaning to their work, hence are dedicated and committed [19,25,57]. Therefore, researchers have persuasively claimed the importance of calling in performing duties [58,59].
As previously mentioned, people that perceive a calling toward their jobs can make commitments beyond expectations and rewards for the fixed goals [19]. In other words, the efforts and the behavior of people pursuing a calling are not limited to formal requirements or prescribed goals. They are willing to make personal sacrifices and spend extra time in their work [60]. People with a calling strive to make the world a better place [61], hence they go above and beyond by, for example, paying attention to details while focusing on distinction [19]. That is why employees perceiving a calling toward their work have extra concern for their duties and additionally exhibit change-oriented OCB, which is a voluntary effort to improve organizational performance, by improving work processes. This is because people with meaning and purpose in their work perform duties more efficiently and experience a higher level of job satisfaction and well-being [59], hence creating a positive virtuous cycle. Employees living in today's rapidly changing world are motivated more by finding interest and meaning in their work rather than extrinsic rewards like money, compared with the older generations [62][63][64][65]. Therefore, calling promotes change-oriented OCB among employees through the mechanism of intrinsic motivation.
The discretionary behaviors of employees that are not recognized by the formal reward system beyond official job skills can be generally considered extra-role behavior [41]. According to previous studies, individuals with a calling participated more in helping other people and social welfare [66]. In the organizational context, employees with a calling toward their jobs tend to participate in OCB [26,27], which promotes organizational efficiency. Calling is expected to also positively influence change-oriented OCB, which is an OCB concept conceptualized by distinguishing only the individual initiative. However, there is no empirical research on the positive effect of calling on change-oriented OCB. Accordingly, this study hypothesized that:

Hypothesis 2. Employees' calling increases their change-oriented OCB.
This study selects calling as a moderating factor that not only affects change-oriented OCB, which is an important element for organizational change, but also strengthens the positive effect of authentic leadership on change-oriented OCB, and examines its effects using the self-determination theory (SDT; henceforth, "SDT") as the theoretical foundation.
SDT is a major theory related to motivation, in which individual behavior must be self-determined. It is further classified by the extent of autonomy in behavioral choice into amotivation, extrinsic motivation, and intrinsic motivation [67]. Intrinsic motivation has the highest level of autonomy, which can be increased when the need for individual competence is fulfilled [68]. According to SDT, employees with a high calling can be intrinsically motivated at a high level, which is related to the perceptive skills of employees [56]. According to previous studies, calling is different from skills but is positively related to self-efficacy [69,70]. Recently, calling perceived by employees was found to increase selfefficacy [26], based on which it can be assumed that employees' calling can help them to role-modeling from authentic leaders. When employees perceive a high level of calling toward their jobs, their desire for increased competence will be fulfilled, and their intrinsic motivation promoted. Therefore, this will strengthen the positive effect of authentic leadership on change-oriented OCB. Such a moderating effect is important because calling is intuitive and is not easily influenced [19][20][21], and can create a positive virtuous cycle as an ongoing process [23,24]. Accordingly, this study assumes that a higher level of employees' calling will promote intrinsic motivation in the process of imitating and learning from authentic leaders, hence strengthening the effect of authentic leadership. Therefore, this study hypothesizes (Please see Figure 1):

Hypothesis 3.
Employees' calling moderates the relationship between authentic leadership and change-oriented OCB, such that the association will be stronger when calling is high (vs. low).

Sample and Data Collection
The participants of this study are full-time employees working at a private enterprise in South Korea. This company has more than 1500 employees. The survey was conducted through a reliable online data collection platform, Macromill Embrain, with 6.4 million survey panels in South Korea. The first round of surveys began in May 2020 and lasted for approximately two weeks, and responses were obtained from 607 participants. The second round of surveys took place one month later, in June 2020. The data from 485 respondents who participated in both surveys were used during the final analysis. This study collected data in two stages to prevent common method bias (CMB; henceforth, "CMB"). In the initial stage, employees measured their perceptions of leadership and calling. A month later, change-oriented OCB was measured among the employees that participated in Stage 1. Data collection in a longitudinal study requires the elaboration of having to collect data from the same participants at the same time intervals, which is why a specialized survey company was requested to help with the survey.
To test the above-mentioned hypotheses, an online survey was conducted twice with the employees of the private enterprise in South Korea. The independent and moderating variables were covered in the first survey to prevent CMB. Further, the same participants were asked about the dependent variables after four weeks. A total of 608 and 490 participants responded in the first and second surveys, respectively. The data from 485 respondents were used in the final analysis; 13 copies of the questionnaire that contained partial or insincere responses were excluded. The demographic characteristics of the respondents are as follows. There were 247 men (50.9%) and 238 women (49.1%); 92 respondents were in their 20s (18.9%), 215 in their 30s (44.3%), 135 in their 40s, (27.9%) and 43 in their 50s or above (8.9%), showing that most of them were in their 30s. There were 23 high school graduates (4.7%), 76 junior college graduates (15.7%), 317 university graduates (65.4%), 61 masters (12.6%), and 8 doctors (1.7%). Regarding the job level, most were on the associates to assistant manager level (254, 27.8%) followed by manager level (109, 22.5%), deputy/general manager level (54,22.5%), and executive level or higher (22, 4.5%). Regarding tenure (in years), 249 respondents had worked for 1-4 years (51.4%), 109 had worked for 5-9 years (26.4%), 54 had worked for 10-14 years (13.5%), and 22 had worked for 15 years or more (8.7%).

Measures
A five-point Likert scale rated on scores of 1 ("strongly agree") to 5 ("strongly agree") was used in the questionnaire. The English questionnaire was translated in Korean. To ensure the reliability and validity of the research tool, this study used a standard translation and back-translation procedure [71].

Authentic Leadership
Regarding authentic leadership, 16 items of the ALQ were used and measured in Time 1. The specific survey items included "My leader encourages everyone to speak their mind", "My leader demonstrates beliefs that are consistent with their actions", and "My leader analyzed relevant data before making a decision". Cronbach's alpha of the survey items was 0.95, which is higher than the standard for reliability, that is, 0.70 [72].

Change-Oriented OCB
Regarding change-oriented OCB, five items of the measurement tool by Morrison and Phelps [40] were used and measured in Time 2. The specific survey items included: "I make constructive suggestions to improve the work performance of the department", "I constantly ponder over problems or difficulties faced by the department and strive to solve them", and "I make efforts to improve unnecessary or ineffective work methods and procedures". Cronbach's alpha of the survey items was 0.95.

Calling
Regarding calling, five items developed by Bunderson and Thompson [66] were used. This survey is based on previous studies on the meaning of work [21,58,73]. The survey was measured in Time 1. The specific survey items included: "I have a meaningful job", "What I do at work makes a difference in the world", and "The work that I do is meaningful". Cronbach's alpha of the survey items was 0.90.

Control Variables
Control variables included gender (1 = female) and tenure (in years), as mentioned in previous studies. Choi [4] mentioned that compared with female employees, male employees are less reluctant to do destructive activities that overturn the customs and processes of the organization to which they belong. Moreover, Seppälä et al. [5] claimed that the change-oriented OCB of employees that worked longer in the organization will be better accepted by other employees. Along with age, job level, and the education level that are examined to have significant correlations, OCB was included in the control variables.
A dummy variable was used (0 = male and 1 = female). Tenure (in years) was further measured on a scale of six levels from less than 1 year to 20 years, by asking the respondents how many years they had worked in the company at the point of the survey. Age was measured on a scale of five levels from 10s to 60s and above. Education level was measured on a scale of five levels from high school graduates to doctors or higher. Job level was measured on a scale of six levels according to the company's job level system from associate to executive levels.
In conclusion, OCB was added. Further, the classic concept of OCB is the root of change-oriented OCB, which is a key dependent variable examined in this study [1] and is similar to change-oriented OCB. Moreover, the OCB-O concept is similar to the changeoriented OCB that arises from the motivation to pursue effectiveness in organizational management in addition to one's own work as a discretionary behavior for organizational improvement. This is examined by the high correlation between the two variables (r = 0.76, p > 0.01). Therefore, to closely verify the effect of authentic leadership and calling on change-oriented OCB, we controlled for OCB. OCB was measured using three items by Buil et al. [74], constructed based on the concept of OCB-O by Lee and Allen [75] and rated on a five-point scale.

Common Method Bias
This study used Harman's single-factor test proposed by Podsakoff et al. [76] to verify the effect of CMB. Therefore, all the factors were analyzed using confirmatory factor analysis [77]. The result showed that a single factor does not explain more than 11.69% of the covariance among variables. Based on this result, the CMB was considered insignificant.

Analysis Strategy
This study used Stata 16.1 version (Data Analysis and Statistical Software, Stata Corp., College Station, TX, USA) to conduct the empirical analysis. The variance inflation factors (VIFs) were confirmed with a mean centering of variables before conducting all the analyses. All the VIFs were below 10, proving that there was no multicollinearity problem [76]. CFA and Cronbach's α were further used to test for reliability and validity. CFA was conducted by calculating the model fit index. Moreover, correlation and reliability analyses were conducted, for which the Cronbach's α of each variable was obtained, showing a value higher than 0.70. In conclusion, to test the hypotheses of this study, the means of all the item measures of each variable were obtained to conduct a correlation analysis of the variables along with a hierarchical multiple regression analysis.

Validity Analysis
CFA was conducted for validity analysis, proving that the key variables used in the models were distinguished with discrimination. The indices examined were the comparative fit index (CFI), Tucker-Lewis index (TLI), standard root mean square residual (SRMR), and the root mean square error of approximation (RMSEA). Generally, a model is considered fit when the CFI and TLI are above 0.90, the RMSEA is below 0.08, and the ratio of the absolute fit index (CMIN) and degree of freedom is below 3 [78][79][80]. As shown in Table 1 Table 2 shows the means, standard deviations, and correlations of the variables. The relationships among the variables presented in the model are mostly consistent with the ones presented in the hypotheses. First, gender, age, education, job level, and tenure, which were selected as control variables, show a high correlation with the variables presented in the research model. Moreover, OCB shows a significant correlation with all the research variables, with a high level of correlation with change-oriented OCB (r = 0. 76, p < 0.01), and is therefore meaningful as a control variable. The independent variable (authentic leadership) and dependent variable (change-oriented OCB) (r = 0. 30, p < 0.01) are positively correlated. This is consistent with the hypothesis that the employees that highly perceive authentic leadership are involved in change-oriented OCB. Calling, which is the moderating variable, shows a positive correlation with authentic leadership (r = 0. 44, p < 0.01), which is the independent variable, and a positive correlation with change-oriented OCB (r = 0. 48, p < 0.01), which is the dependent variable.

Hypotheses Testing
A hierarchical multiple regression analysis was conducted to test the hypotheses proposed in this study. Table 3 shows the results. Hypothesis 1 predicts that authentic leadership perceived by employees positively influences their change-oriented OCB. Model 1 in Table 3 included only the control variables in the analysis. Model 2 added authentic leadership perceived by the employees. Model 3 added calling to Model 1. The explanatory power of Model 2 increased significantly compared with Model 1 (R 2 = 0.60; F = 101.45, p < 0.001). Further, the regression coefficient of authentic leadership is significant toward a positive direction (β = 0.08, p < 0.05). These results support Hypothesis 1.
Hypothesis 2 states that the employees' calling positively influences change-oriented OCB. In Model 3, the regression coefficient of calling is significant toward a positive direction (β = 0.12, p < 0.001), which shows that the explanatory power of Model 2 increased significantly compared with that of Model 1, hence supporting Hypothesis 2.
The result of the moderating effect of calling is as follows. Hypothesis 3 states that calling moderates the effect that authentic leadership has on change-oriented OCB toward a positive direction. In other words, employees who highly perceive that their work is a calling are likely to exhibit a greater effect of authentic leadership on change-oriented OCB. To test this hypothesis, independent variables, moderating variables, and interaction terms were developed and included in Model 4. Before developing the interaction terms, the variables were grand-mean centered as suggested by Aiken & West [81] to prevent the multicollinearity problem and facilitate interpretation. Model 4 shows that the regression coefficient of the interaction term is significant toward a positive direction (β = 0.06, p < 0.05). Therefore, these results support Hypothesis 3. To explicitly determine the interaction effect, simple slopes were drawn as suggested by Aiken & West [81], after which a simple slope test was conducted. Figure 2 shows conceptual lines (simple slopes) that estimated the regression equations at the positions of Mean − 1 SD and Mean + 1 SD from the mean of calling, which is the moderating variable. The result of the simple slope test showed that the simple slope is significant when the moderating variable is at Mean − 1 SD among the slopes of the two regression lines (b = 0.19, n.s.), whereas the simple slope is insignificant when the moderating variable is at Mean + 1 SD (b = 2.03, p < 0.05.). This result supports the assertion that employees with higher calling are likely to exhibit a greater effect of authentic leadership perceived by employees on change-oriented OCB.

Discussion
Based on SDT [67], this study investigated whether and how authentic leadership can promote the employees' change-oriented OCB. This study shows that employees with a high perception of calling exhibited a clearer positive effect as their ability to imitate and learn from authentic leaders increased. By analyzing the surveyed data with a one-month time gap, we obtained a few clear insights along with both theoretical and managerial implications.

Theoretical Implications
This study makes three contributions to studies on authentic leadership and changeoriented OCB.
First, this study creates a link between studies on authentic leadership and changeoriented OCB and responds to the demand for more empirical research on the effect of authentic leadership on employees' change-oriented OCB [10]. The results of the survey emphasize the important role of authentic leaders in encouraging employees' change-oriented behavior. This examined the initial view that the leader's support can promote employees' change-oriented OCB [4,82]. Regarding authentic leadership that has barely received any attention in studies regarding change-oriented OCB, this study determines why this important leadership style can be key in encouraging employees' change-oriented OCB. In other words, authentic leaders with high self-awareness and self-regulation build genuine relationships with employees based on relational transparency and internalized moral perspective when interacting with employees and also show open communication and balanced processing. In this process, employees imitate and learn from authentic leaders and internalize their values [45].
Previous studies show that authentic leadership can increase the effect of changeoriented leadership behavior in the process of change (e.g., [83][84][85][86]) and that change-related values among authentic leaders are transferred to employees, hence affecting their change-oriented OCB. Lee et al. [87] assumed and demonstrated that authentic leadership positively influences employees' change-oriented behavior but failed to show a direct effect, hence fueling the need for various in-depth attempts in authentic leadership and change-related behavior among employees. Accordingly, this study has significance as the first study to examine that authentic leadership serves as a positive antecedent to change-oriented OCB based on the importance of voluntary change among employees in organizational change. Among new voluntary behavioral patterns of individuals toward change as per today's needs [88], change-oriented OCB was selected and verified as the outcome variable, which contributes to not only expanding the research scope of authentic leadership but also inducing further research.
Second, calling had a positive effect that increased employees' change-oriented OCB. Previously, calling had been mostly used as a religious term. However, recently, the term is receiving attention from many researchers on organizational behavior. Its importance has been further emphasized as a goal-oriented attitude toward one's job to improve organizational performance by perceiving work as part of one's life [58,59]. Previous studies show that employees with a calling exhibit altruistic behavior [66] and tend to participate in OCB [26,27]. However, none of them examine that calling positively influences change-oriented OCB.
Third, this study ascertained the key element that moderates the effect authentic leaders have on change-oriented OCB. Previous studies on authentic leadership are constantly raising the need to determine the situational factors [12,13]. This study examined the arguments of researchers that authentic leadership, as a new alternative to leadership that can resolve many difficulties faced by organizations in this era of change, can create sustained performance' that constantly creates new values in the world of new changes [30]. It also examined the positive moderating effect of calling that strengthens such positive effect, which is an important contribution made for authentic leadership to be established as a systematic theory (authentic leadership theory; ALT). Particularly, calling, which one perceives as a meaning of life that must naturally be done by oneself, is even more important as it is sustainable and consistent. This discovery provides a new understanding of calling.

Managerial Implications
Our findings have a few managerial implications. First, the dramatic change in the internal and external work environments in the last few years has made the employees' active behavior more suitable [89]. Employees that exhibit flexible and active work behavior are undoubtedly beneficial to organizations in coping with competition, securing advantages, and succeeding in a dynamic environment [90]. Therefore, the following suggestions can be made to achieve performance improvement through change-oriented OCB, which pursues a voluntary raise in the effectiveness of organizational operation methods.
First, as the positive correlation between authentic leadership and change-oriented OCB has been demonstrated, it is important that organizations build an environment where authentic leadership can be fostered. Only when an inclusive organizational climate where authentic leaders and employees can continuously learn and grow is established can authentic leadership be developed [28,29]. Since the influence of an authentic leader is significant only when the role is not forced, but rather the person is voluntarily viewed as a role model by employees, it is crucial that an environment to develop authentic leadership is formed at the organizational level.
Second, it is necessary to constantly manage the influence of OCB, which is the change-oriented and voluntary behavior of employees, to establish sustainable management. Leadership plays an important role in fostering and improving the behaviors and actions of employees at workplaces [91], and it has been confirmed that authentic leadership has a positive effect on employees' change-oriented OCB.
Third, employees' calling directly influences their change-oriented OCB, which triggers organizational change and strengthens the effect of authentic leadership on changeoriented OCB. Therefore, organizations must pay more attention to the calling perceived by employees. Helping employees find meaning and have fun in their work enhances meaning in career and life, resulting in calling [92]. Furthermore, organizations can manage and motivate employees using the concept of calling. For example, when choosing job candidates, they can measure their calling through interviews and prioritize those with a high calling [93]. Moreover, they can focus on education and training for the development of calling, such as through programs on the importance of careers. Furthermore, it may also be helpful to emphasize the importance of the organization's mission and vision and connect these ideas to the employees' calling.

Limitations and Future Research
Even though current research has theoretical and practical implications, there are still limitations. First, this study collected data with a time lag to overcome the limitation of CMB methodologically and tested the statistics and models through CFA. This reduced measurement errors by having multiple indices for each latent variable and testing a substitutional model. However, further research can further reduce CMB by separating the respondents [76]. For example, it can examine the effect of authentic leadership perceived by employees on their change-oriented OCB perceived by leaders and examine the moderating effect of the calling perceived by employees. Second, it is examined that authentic leadership has a positive effect at the individual level on organizational performance e.g., [94][95][96][97]. However, researchers recommend the examination of employees' positivity or organizational citizenship behavior at the group level Walumbwa et al. [31]. Therefore, multilevel and cross-level analyses must be used in future research to comprehensively examine the relationship between authentic leadership and change-oriented OCB. Finally, the results of this study from a South Korean organization may differ from those from other countries. For example, the Asian society tends to be more collectively and hierarchically organized than the Western society [98]. Therefore, South Korean samples may be more affected by the social environment than the Westerners [4]. Useful implications on authentic leadership can be obtained by collecting and analyzing data from employees in the United States or Europe and analyzing change-oriented OCB subdivided by job level and tenure (in years).

Conclusions
This study provides important implications by examining moderators: employee's calling, which can strengthen the positive influence of authentic leadership on the subordinate's change-oriented OCB.
Funding: This research received no external funding.