Alteration of Instruments

The alteration of an instrument materially changes it. The document no longer reflects the terms that the parties originally intended to serve as the basis of their legal obligation to each other. To be material, the change must affect an important part of the instrument and the rights of the parties to it. Any material alteration relieves the nonconsenting party of any obligation to perform according to the terms of the instrument. If the altered instrument is a contract, then the original contract is void. The nonconsenting party cannot be legally obligated by the new contract since he or she never agreed to it. A document that has been materially altered does not regain its original validity if it is restored to its original form by erasing or deleting unauthorized words.

The date of an instrument is often considered a material provision when it establishes the time within which the parties to a document must perform their obligations under it. An unauthorized change of date that shortens the time of payment or extends the time of performance so that more interest will become due is a material alteration.

An alteration of a signature that changes the legal effect of an instrument is material. Erasing words that show that the signer is acting as an agent, for example, changes the signer's liability under the instrument and, therefore, is a material alteration. However, when a signature that was improperly placed on a document is erased, there is no material alteration since the legal meaning of the document is not changed.

Any change in the terms of the instrument that affects the obligations of the parties is material. In a contract to sell land on commission, a change in the rate of commission is material. A change in a description in a deed so that it transfers a smaller piece of land, a change in the name of a purchaser in a sales contract, or an alteration in the terms of financing set forth in a mortgage is also material.