Hello Aspirant,

Yes definitely you can do so. Suppose you took admission in Jadavpur University using your WBJEE score and later on in September your JEE-Main result will be declared and there if you got good score for which you are sure that they can take you to any of your dream NIT or whatever NIT you want then you can appear for JOSAA counselling and if the satisfying seat is allotted to you then you can withdraw your admission from Jadavpur University and your documents will be returned back but note that some portion of your amount deposited in the college might get deducted as admission charges and some other miscellaneous charges.

I hope this information helps you.

Good Luck!!