Section 26(2)(i) in West Bengal Municipal (Employees' Service) Rules, 2010
(i)A person continues in service if he withdraws his resignation letter before the date from which the resignation is to take effect. The resignation becomes irrevocable and operative after the aforesaid date of resignation. So the question of withdrawal of the resignation letter by the employee and taking back such employee in service goes not arise. After the resignation has become irrevocable and effective it cannot be cancelled.