The Proxy becomes effective when your doctor determines that you are unable to make or communicate health care decisions. Your doctor then must record in the chart the cause and nature of your incapacity as well as its extent and probable duration. In order to appoint an Agent, you must be at least 18 years of age. You do not need a lawyer to fill out the form and make it legally binding. In order for it to be binding, you must sign the form in the presence of two adult witnesses, neither of who are either your Agent or your Alternate Agent.