(a) Capacity to amend.— While having the capacity to make mental health decisions, a declarant may amend a declaration by a writing executed in accordance with the provisions of section 5822 (relating to execution).
(b) Determination of capacity.— During the period of involuntary treatment pursuant to Article III of the act of July 9, 1976 (P.L.817, No.143), known as the Mental Health Procedures Act, a declarant may amend the declaration if the individual is found to be capable of making mental health decisions after examination by a psychiatrist and one of the following: another psychiatrist, a psychologist, family physician, attending physician or mental health treatment professional. Whenever possible, at least one of the decision makers shall be a treating professional of the declarant or principal.