Section 10584 Of Chapter 4. Notice Of Proposed Action Procedure From California Probate Code >> Division 7. >> Part 6. >> Chapter 4.

. (a) A waiver or consent may be revoked only in writing and is effective only when the writing is received by the personal representative.
  (b) A copy of the revocation may be filed with the court, but the effectiveness of the revocation is not dependent upon a copy being filed with the court.