You can put in a service request using the link given below:

http://www.insurancepandit.com/support/service_request.php

You will get the endorsement on the same day if your policy has not started. But if your policy has already started, endorsement can only be made after proper evidence for the required change is given.

If you are in a hurry and have to leave immediately, it is advisable to buy a new policy and put a request using the above link for cancellation of your earlier policy. The amount will be refunded to your account within 4-5 working days.