20 Pa.C.S. § 2505: Revocation of a will.

No will or codicil in writing, or any part thereof, can be revoked or altered otherwise than:

(1) Will or codicil.--By some other will or codicil in writing;

(2) Other writing.--By some other writing declaring the same, executed and proved in the manner required of wills; or

(3) Act to the document.--By being burnt, torn, canceled, obliterated, or destroyed, with the intent and for the purpose of revocation, by the testator himself or by another person in his presence and by his express direction. If such act is done by any person other than the testator, the direction of the testator must be proved by the oaths or affirmations of two competent witnesses.