I want to release myself as a cosigner.

This is one of the many reasons one should never cosign for another person. The lender only agreed to lend money to this person based on your co-signing, so it had another person to hold accountable if and when this person failed to pay on the loan. While I can certainly appreciate your desire to no longer be on the note as a co-signer, there is no way that the lender will release you from that obligation. Put yourself in the lender position - if you had two people that you could hold liable for a debt, one of which was a better credit risk than the other, would you agree to let the better credit risk go?