If you want to correct the details as misprinted or incorrect details on your admit card, you have to visit the regional office of your board. Now to get the details about the regional office of your board, you need to visit the google and visit the official website through which you can get the details of contact for your board.

You have nothing to be tensed about but you need to keep some patience and it can take some time to get the corrected copy. You can also visit your school, they can also provide you some contacts and advise regarding the procedure to do so.

I hope my answer give you some insight! All the very best!!