(a) The authority of an attorney-in-fact under a power of attorney may be revoked as follows: (1) In accordance with the terms of the power of attorney. (2) Where the principal informs the attorney-in-fact orally or in writing that the attorney-in-fact`s authority is revoked or when and under what circumstances it is revoked. This paragraph is not subject to limitation in the power of attorney. (3) Where the principal`s legal representative, with approval of the court as provided in Section 4206, informs the attorney-in-fact in writing that the attorney-in-fact`s authority is revoked or when and under what circumstances it is revoked. This paragraph is not subject to limitation in the power of attorney. (b) An attorney-in-fact or third person who does not have notice of the revocation is protected from liability as provided in Chapter 5 (commencing with Section 4300).