Compared to private firms, public companies generally have excess labor force. During the privatization process and conversion of a public enterpriseto a private enterprise, new employers tend to adjust their labor force in order to reduce ongoing costsand improve the company's economic goals.In order to persuade the employees to accept voluntary retirement and leave the firm, these firmsmay offer a reward to the employees that are eligible for optional retirement but are not eligible to mandatory retirement. Employees tend to receive the highest possible premium and in contrast the firm is willing to pay employees the minimum possible premium. In this paper, we consider the options facing employer and employee through dynamic games with complete information. Games between employee and employer was shown in the form of an extensive game.Minimum premium required to accept the optional retirement was calculated using subgame perfect equilibrium (SPE) and the effect of ceiling premium has been studied on minimum premium. The calculations show that the reductions in mandatory retirement age, the retirement benefits from social security organizations, expected interest rate and the maximum years of service and an increase in employee's age and her years of service lead to a reduction in the minimum premium required to accept the optional retirement. Moreover, due to lower mandatory retirement age for women than men in many countries, women accept optional retirement with lower premium. The proposed ceiling premium will also cause to refuseoptional retirement from the part of the workers with high salary, young and lownumber of years of service.