Hi Vihaa Harish.
Normally what you have to do is while accepting your seat that you got in round 2, you have to choose for upgradation in coming rounds. This procedure can different for different colleges or states. FOr JoSAA, you have to choose the float option. And in some cases, you have to do that while admission. PLease go through the guidelines of the admission procedure.
Good Luck.
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