(a) A will or any part thereof is revoked by a subsequent will which revokes the prior will or part expressly or by inconsistency.
(b) A will is revoked by being burned, torn, canceled, obliterated, or destroyed, with the intent and for the purpose of revoking it by the testator or by another person in his or her presence by his or her consent and direction. If the physical act is by someone other than the testator, consent, and direction of the testator must be proved by at least two witnesses.