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 And a will that has been revoked in part may be admitted to probate—but the revoked provisions will not be effective.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 South Carolina, a will may be revoked by the testator in several ways. A testator can create a new will or codicil that explicitly states the revocation of all previous wills or specific provisions. This is known as express revocation. Additionally, a will can be revoked by implication if a later will or codicil makes a different disposition of property that is inconsistent with the earlier will. For a holographic will (a will written entirely in the testator's handwriting), the testator can revoke part of it by making changes directly on the document without the need to re-sign or initial the changes. For an attested will (one witnessed by others), revocation of part of the will must be done with the same formalities as creating a new will, or by executing a new will that expressly revokes prior ones. A testator can also revoke a will by physically destroying it, such as by tearing, burning, or otherwise rendering it unusable. Once a will is revoked, it can only be reinstated if it is re-executed with the required formalities or republished through a codicil.