The law regarding the requirements for revoking a will varies from state to state. But a will generally may be revoked, in whole or in part, by a subsequent will, codicil, or written declaration executed with the formalities of making a will, or by the testator destroying or canceling the will, or causing it to be destroyed or canceled in his presence. And a will that has been revoked in part may be admitted to probate—but the revoked provisions will not be effective.

A will can be expressly revoked—in whole or in part—by inserting a revocation clause in a later will, codicil, or written declaration stating that the testator revokes all prior wills and codicils—or by revoking a specific bequest in an earlier will ("I revoke my bequest to the University.").

Or a will can be revoked by implication, in whole or in part, when the testator makes a different disposition of identical properties in a subsequent will, codicil, or written declaration. In this instance, the later will or codicil revokes the earlier will or codicil—but only to the extent the two are inconsistent.

And the testator can cancel the entire will by marking through all of the dispositive provisions of the will, or writing "canceled," "void," or "annulled" through the signature line, or through all of the dispositive provisions. The testator can cancel part of a holographic will by making changes to one or more provisions in the will. There is no requirement that the testator re-sign the holographic will after making changes to it, or initial the changes. For an attested will (signed by attesting witnesses), the testator can cancel part of the will by making changes with the same formalities required for an attested will—or the testator can execute a new will, expressly revoking all prior wills and codicils. And the testator can revoke the entire will by destroying it—such as by shredding, tearing, or burning it.

Once a will is revoked, it remains revoked unless it is re-executed with the necessary formalities, or is republished by a codicil.

In Mississippi, the revocation of a will can be accomplished in several ways. A testator may revoke a will, either entirely or in part, by creating a subsequent will, codicil, or written declaration that is executed with the same formalities required for making a will. This includes expressly stating the revocation of all prior wills or specific provisions within them. Additionally, a will can be revoked by implication if a later document makes a different disposition of the same property, thereby creating inconsistencies with the earlier will. For physical revocation, the testator can cancel the will by defacing it, such as by crossing out dispositive provisions, writing 'canceled,' 'void,' or 'annulled' on the signature line, or destroying the document entirely through shredding, tearing, or burning. Changes to a holographic will (a will written entirely in the testator's handwriting) do not require re-signing or initialing. However, for an attested will (one witnessed by others), any partial revocation must be done with the same formalities as the original will, or by executing a new will that expressly revokes prior wills and codicils. Once a will is revoked, it can only be reinstated if it is re-executed with the necessary formalities or republished by a codicil.