Hey Akhila !

In that case, if you are upgraded to your better preferred college in the 2nd Round of AIIMS Counselling, then you must go to the previously alloted college and pick up the submitted documents as well as certificates for taking it to your newly alloted college in Round 2. Don't worry about the payment of the fees. The fees that you paid in the college in Round 1 is transferred under your name to the newly alloted college. Hence, no issues of further fee payment.

Good Luck !