Yes. It is not required to get a seat in first round to participate in second round.

You will not be required to report at reporting centre.

It will be automatically considered that you have chosen "float" option during seat acceptance time after first round and will be allowed to participate in next round.

The same is repeated if you not get any seat in second round. ( ie. you will be allowed to participate in third round ).

But once you get a seat in any of the rounds you will have to report at reporting centre during seat acceptance period to pay seat acceptance fee and documents verificationeven if you do not want that seat but want to choose float or slide option at reporting centre.