Montana Title 26. Evidence § 26-1-106. Explanation of alterations in a writing

The party producing a writing as genuine that has been altered or appears to have been altered after its execution in a part material to the question in dispute shall account for the appearance or alteration. The party may show that the alteration was made by another without the party's concurrence, was made with the consent of the parties affected by the alteration, or was otherwise properly or innocently made or that the alteration did not change the meaning or language of the instrument. If the party does that, the party may give the writing in evidence, but not otherwise.