Hi,
I hope you are doing well.
No you can't change your board after you have taken an admission and got registered under the board for 12th. The registration for 12th is done in 11th standard after the admission process is completed in the college.
after 11th means you have already studied one year and you can't change it now.
Regular exam updates, QnA, Predictors, College Applications & E-books now on your Mobile