According to Mont. Code Anno., § 28-1-1401, an accord is an agreement to accept in extinction of an obligation something different from or less than that to which the person agreeing to accept is entitled. The parties to an accord are bound to execute it. It does not extinguish the obligation until it is fully executed. Mont. Code Anno., § 28-1-1402 states that acceptance by the creditor of the consideration of an accord is called satisfaction and it extinguishes the obligation.
However, part performance of an obligation, either before or after a breach thereof, when expressly accepted by the creditor in writing in satisfaction or rendered in pursuance of an agreement in writing for that purpose, though without any new consideration, extinguishes the obligation, according to Mont. Code Anno., § 28-1-1403.