Revocation of a legacy or other testamentary provision occurs when the testator:
(1) So declares in one of the forms prescribed for testaments.
(2) Makes a subsequent incompatible testamentary disposition or provision.
(3) Makes a subsequent inter vivos disposition of the thing that is the object of the legacy and does not reacquire it.
(4) Clearly revokes the provision or legacy by a signed writing on the testament itself.
(5) Is divorced from the legatee after the testament is executed and at the time of his death, unless the testator provides to the contrary. Testamentary designations or appointments of a spouse are revoked under the same circumstances.