Hello Joyitri

According to the MBBS admission procedure once you have been alloted the seat you have to join the college for participating in further rounds. First you have to take admission in first round then you can upgrade in consecutive rounds if you are eligible. If you are not satisfied then you can leave the seat with loss of registration fees. For more information go through the link given below

https://medicine.careers360.com/articles/neet-counselling

Thank you.