Hello Student

After attending all the JOSSA round you can appear for CSAB round after withdrawing your seat allotment and  applying for as a fresh candidate in CSAB.if you do not withdraw your seat allotment it will be automatically cancelled as for as you are attending the  special round for selection of seat allotment. If you pay for the seat allotment allocation fees then it will be adjust it for the next round.

Hope for the best.