(a) A patient having capacity may revoke the designation of an agent only by a signed writing or by personally informing the supervising health care provider.(b) A patient having capacity may revoke all or part of an advance health care directive, other than the designation of an agent, at any time and in any manner that communicates an intent to revoke.EFFECTIVE 7/1/2000. Added10/10/1999 (Bill Number: AB 891) (Chapter 658).