Hello aspirant,
If you have by mistake written GM in place of OBC -ncl then you should correct it during the correction period only as now nothing can be done as you have to go forward like this or cancel your registration and if in another round process the new registration or another way is to write a mail to the councilling help desk as they can only help you.
Hope this helps
If any queries feel free to ask
All the best!!
Regards
Regular exam updates, QnA, Predictors, College Applications & E-books now on your Mobile