Montana Code Annotated · § 28-2-1703 — Extinction of executory obligations of contract by destruction, cancellation, or alteration

(1) The intentional destruction, cancellation, or material alteration of a written contract by a party entitled to any benefit under the contract or with the party's consent extinguishes all the executory obligations of the contract in that party's favor against parties who do not consent to the act.

(2) When a contract is executed in duplicate, an alteration or destruction of one copy while the other exists is not within the provisions of subsection (1).