Provided that a part-time employee may, by mutual agreement between the employer and the worker, receive a charge of 25 % of his hourly rate and is not entitled to annual leave, sick leave or payment for public holidays, and provided that the payment of a charge of the hourly rate does not affect the status of part-time employee. 17.6.3 Within the framework of flexible working time, the periods of commencement and separation from service shall be subject to the agreement between the employer and the worker. 7. . .