First things first, you cannot appear for NEET PG Counselling other than in any other Category that you initially have selected while filling during the application form. You cannot change your Category after the correction window closes. For example, if you have selected OBC as your Category during filling the application form, it will stay the same even during Counselling because the merit list has been prepared according to the Category you have chosen while filling up the NEET PG application form. So you cannot make any changes to that now. You cannot attend for Counselling under General Category.