It's unlikely the bank will agree to take anyone off until the debt is paid - right now they can pursue either or both of you for the money and there is no reason for them to release any of their rights.

If you are a good credit risk in your own right, they may agree to the debt becoming yours, in which case they will probably open a new account in only your name and transfer money from that account to settle the original debt, leaving you responsible for the balance on your own.