sir i fill jee mains form in rbse board.can i change another board after jee mains exam or before exam

Hello Abhay,
As you are in class 12 and your exam is going on.
Please focus on the subject you remain, perform well in remaining subject exam first.
Be self confident and keep calm during giving the exam.
Dont think at this moment about changing the board.

Yes you can change your board after exam if you want or in case of improvement and all .
Candidate only think about how can you well in remaining exam with calm nature.

If I don't get your questions than please elaborate your question so I can provide you guidance in best possible manner.

Regards...