Hii

As of now you can not make any changes in the application form of AIIMS if you have submitted it.
Once the basic registration ends on 14th januray, then a correction window will start from 17th of january till 22nd january. If the application is rejected or has any deficiencies, you will be able to make the required corrections during this time period. No other chance is there for corrections.
Also i will suggest that you do ask then on the help portal once about the issue so that you would be sure that during correction period you can make the changes.The help portal is available on the dashboard once you login to your account.

Hope this helps
Thanks!!