Yes, it is mandatory that students give pre-boards before CBSE as some schools say, however it is mandatory to send the notes to the board. Most schools prefer these pre-tables to test whether the student is ready for the board exam or not.

So if your school wish to take pre-boards then you have to give it and on their permission only you will get the hall tickets so contact them and see if there are some provisions out there.

I hope this answer helps. All the very best for your future endeavors!