A codicil is a document that a testator can use to modify his or her will after it has been executed. The codicil functions like an amendment or supplement, and allows the testator to modify or partially revoke the will, without having to execute a new one.
In order to execute a valid codicil, the testator must adhere to the same minimum requirements for drafting a valid will. A codicil is usually attached to, or at least stored with, the will it modifies so that both the will and the codicil are found after the testator’s death.