Alteration of Instruments

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Alteration of Instruments

A change in the meaning or language of a legal document, such as a contract, deed, lease, or Commercial Paper, that is made by one party to the document without the consent of the other after it has been signed or completed.

If such a change is made by a third party without the consent of either party to the instrument, it is called a spoliation or mutilation.


The face of an instrument is changed by its alteration. A difference in handwriting, a change in words or figures, an erasure, and the striking out of particular words are some methods used to alter an instrument. Since there must be a change in the meaning or language of a document, retracing an original writing—as when a figure written in pencil is retraced in ink—is not an alteration.

Material Changes

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.

Time of Alteration

A modification in a document before its completion is not an alteration. The parties are bound to review the document and to have agreed upon its terms before executing it. In order for an alteration to nullify the legal effect of an instrument, the change must be made after its completion.


A material change must be intentionally made. The motive behind the alteration is unimportant. If a mistake or accident causes a change, this is not considered a material alteration, but the document may be reformed or rescinded.

The Person Making the Change

The change to the instrument must be made by a party or someone authorized by him or her to do so. No change made by a third person without the consent of either party to the document will invalidate it if its original terms can be learned. When a material alteration is made by a party to commercial paper, such as a check or promissory note, the paper will be enforced as originally written against the party who made the changes.

Consensual Alteration

A change in an instrument made with the consent of the parties is binding upon them. Such consensual alteration is usually evidenced by the signing by each party of his or her initials and the date that the agreement to the changes to the instrument was reached.