If I cancel seat alloted in CSAB 1st round , will that alloted seat again comes again in 2nd round of CSAB??
No it is not necessary that if you have been alloted a seat in first round then you should necessarily be able to get it in the 2nd round also. Therefore you should carefully decide that whether you wish to retain the seat or leave it and choose likewise. However after the second round you wont be able to surrender your seat. Hope this helps.