What document must accompany a major change to a will to ensure validity?

A codicil is a legal document used to make changes or modifications to an existing will. When a significant alteration to a will is necessary, it is not sufficient to simply write a new version of the will; rather, the change must be formally recognized to ensure it is valid under the law. A codicil provides a way to specify what changes are being made, while also reaffirming the rest of the will.

In addition, a codicil must be executed with the same formalities as the original will—typically requiring signatures and sometimes witnesses—making it a legally sound method to amend a will without needing to entirely rewrite it. This ensures clarity and legal recognition of the changes, reducing the risk of disputes regarding the testator's intentions after their death.

Other documents mentioned, such as a durable power of attorney and a living trust, do not serve the same purpose. A durable power of attorney is related to managing someone's affairs while they are alive, and a living trust deals with asset distribution during life or after death, but neither directly addresses modifications to a will.