Hi

You are pointing to special rounds conducted by CSAB (central seat allocation board) to fill the rest of the vacant seats left after round 6 of JOSAA counselling at NITs, IIITs and GFTIs.  They conduct 2 rounds in CSAB.

St udents who were not allotted any seat in JoSAA or whoever wants to upgrade their previously allotted seat in NITs, IIITs and GFTIs can participate in CSAB Special rounds 2021.  The registration is completely online for participating in CSAB special rounds. A valid JEE Main score is the eligibility to participate for the special rounds CSAB conducts. As for the dates it will be posted in the website below

https://csab.nic.in/webinfo/Page/Page?PageId=1&LangId=P

If this is not what you asked pls let me know politely!