Hello Aspirant,

I am writing the condition under which you can do above process.

Suppose you passed your class 12th this year so you are eligible for JEE-Advance 2021 and 2022 provided that you qualify JEE-Main 2021 and 2022. Now you appeared for JEE-Main 2021 and got good rank and got qualified for JEE-Advance then somehow in JEE-Advance you did not score well but due to good score in JEE-Main you can easily get any NIT so you take admission in the allotted NIT and then what you can do is next year in 2022 you have to again appear for JEE-Main and qualify it and then appear for JEE-Advance 2022 and if you score good marks in JEE-Advance then you can definitely withdraw your admission from current NIT and can transfer to IIT on the basis of your JEE-Advance rank.

Also note that even if you have not appeared for JEE-Advance 2021 then also you can appear for JEE-Advance 2022.

I hope this information helps you.

Good Luck!!