Yes,u can change. Only thing u have to do is to apply for the migration certificate, migration certificate means to migrate/transfer from one board to another board of education. In your case, this is from  Rajasthan board to CBSE board.

I would advise you not to change your board from RBSE to CBSE at this time.

All the very best and good luck.

Hello Jatin Sharma. Thanks for contacting Careers360 and we hope we will be able to answer your query.

I would advice you not to change your board from RBSE to CBSE at this crucial stage of your life. 

Two reasons:

• You will find it difficult to cope up with a sudden change in level of difficulty in the two syllabi. It is better if you continue to study in RBSE. 
• And second, nothing is going to happen if you change your board. Note that JEE Mains does not include your 12th marks now. It is enough that you pass the exam. 

So, please don't change. All the best!