You can defer or postpone your staging date up to 3 months. Once you complete the postponement period, you cannot apply another period of postponement, even if you postpone for less than the 3 months permitted.To setup the auto enrolment deferment policy, follow the below road map.

Road Map :
Pension -> Auto Enrolment Deferment Policy Setup -> Click the Edit button -> Click the Save button.
('Pension' is the button positioned in the tasking zone menu at the top. It is the third button from the Right)