(a) The obligation of a party to pay the instrument is discharged as stated in this article or by an act or agreement with the party which would discharge an obligation to pay money under a simple contract. (b) Discharge of the obligation of a party is not effective against a person acquiring rights of a holder in due course of the instrument without notice of the discharge.
Discharge and effect of discharge
D.C. Code § 28:3-601, under Discharge and Payment..
D.C. Code § 28:3-601