Hello Aspirant,

You can cancel or withdraw yourself from the allotted seat but make sure you return the original admission order, bank challan, green card and verification slip, failing which you will not be allowed to surrender or cancel the seat.According to the cancellation policy of CET ,if the candidate wants to surrender the allotted seat in first and second round before the last date of option entry for second extended round will be refunded the fee after deduction of Rs. 5000 as a processing fee.If you have been allotted seat in first or second round but has not reported to the college and cancel the seat after second extended round completion then your entire fee will be forfeited. So your complete fee will be forfeited as you are cancelling the allotted seat in the second extended round.

https://engineering.careers360.com/articles/kcet-seat-allotment

All the best