Cal. PROB § 4734

(a) A health care provider may decline to comply with an individual health care instruction or health care decision for reasons of conscience. (b) A health care institution may decline to comply with an individual health care instruction or health care decision if the instruction or decision is contrary to a policy of the institution that is expressly based on reasons of conscience and if the policy was timely communicated to the patient or to a person then authorized to make health care decisions for the patient.