A declaration becomes operative when (i) it is communicated to the attending physician and (ii) the declarant is determined by the attending physician to be in a terminal condition and no longer able to make decisions regarding administration of life-sustaining treatment. When the declaration becomes operative, the attending physician and other health care providers shall act in accordance with its provisions and with the instructions of a designee under section 187(a) of this title or comply with the transfer provisions of section 193 of this title.