Dear aspirant

First of all I am explaining you in short the rule of choice  filling.During choice filling you can put any no of choices there and sort them according to your favourable interest . In every round you will be allotted only one department of one college . According to your sorted choice list the top most available choice with vacant seats will be given to you . If you are happy with that then you lock that and get admission . Otherwise you upgrade( slide or float) If any of the preceding choice's  seat  becomes vacant then you will get than otherwise you get the allotted seat given to you from the previous round. But under any circumstances you can't get the receding choices after you are allotted a particular option.That's how it works. So choice filling and seat allotment is very vital.

So if you don't get anything new college or department in round 2 then you will get the seat of round 1 and if you get something new then the old option that is the 1st round alotted seat is gone from you.

So if you do a mistake in freezing and go for another upgradation then you have to wait for your 3rd round result . Same probable things can happen as I have mentioned.

Best Wishes.