By special, ethic codes, which should be as part of agreement between employer and employee. 

Perhaps by the code of conduct. 

Some related articles:

Weaver, G. R., & Treviño, L. K. (1999). Compliance and Values Oriented Ethics Programs: Influenceson Employees’ Attitudes and Behavior. Business Ethics Quarterly, 9(2), 315-335.

Treviño, L. K., & Weaver, G. R. (2001). Organizational justice and ethics program “follow-through”: Influences on employees’ harmful and helpful behavior. Business Ethics Quarterly, 11(4), 651-671.

Velasquez, M. G., & Velazquez, M. (2002). Business ethics: Concepts and cases (Vol. 111). Upper Saddle River, NJ: Prentice Hall.

Yes, ethics should be as part of the agreement, but can we manage it by force of management functions or activities?

Many thanks for your interesting opinion  Mr. George G. Tumanishvili

Hi, Mr. Arthur So, first of all, I would like to thank you for your contribution by answering my question, could you please verify your own opinion regard this issue of the possibility of forcing this ethic by management?

It will be good to have some trainings. 

Thanks for your valuable contribution, but is it possible to manage employees ethics if you passed training course regarding this issue?

Thank you, dear Mr. George G. Tumanishvili 

May (2013) demonstrates that challenges exist in organizational communication in ethical decision-making and practice. May deduces that organizational ethics are merely governing the actions of individuals - “organizations do not make decisions, per se, people do” (p. 11). Furthermore, May illustrates that there are challenging ethical questions at the personal, organizational, and societal levels. 

Here is the reference of May's book, which should be interesting to your question:

May, S. (2013). Introduction: Ethical perspective and practices. In Case studies organizational studies: Ethical perspectives and practices (pp. 1-33). Thousand Oaks, CA, USA: Sage Publication Inc.

thank you, colleague Arthur So for the valuable answer 

Regards