In Tamil Nadu NEET PG counselling, Round 2 is conducted after Round 1 vacant seats are announced. In this round you can upgrade from Round 1 seat.

Fresh registrations are also allowed (depending on official notice). Cutoffs usually go down slightly, giving chances to lower-rank candidates.

If you want guidence in your councelling you can check this: https://www.careers360.com/campaign/neet-pg-counselling-companion

Thank you and all the best!