An advance directive gives instructions on the kind of medical care you would like to receive should you become unable to express your wishes yourself, and it often designates someone to make medical decisions for you. Each state has its own laws setting forth requirements for valid advance directives and health care proxies. For example, some states require two witnesses, other states require one witness, and some states do not require a witness at all.
Most states have provisions accepting an advance care directive that was created in another state. But some states only accept advance care directives from states that have similar requirements and other states do not say anything about out-of-state directives. States can also differ on what the terms in an advance directive mean. For example, some states may require specific authorization for certain life-sustaining procedures such as feeding tubes while other states may allow blanket authorization for all procedures.