an advance directive is a legal document that sets forth your preferences related to health care, such as your refusal of or request for medical treatment, or the selection of a chosen healthcare… read more an advance directive is a legal document that sets forth your preferences related to health care, such as your refusal of or request for medical treatment, or the selection of a chosen healthcare agent. this official legal document provides a record of your decisions to healthcare facilities, and it will certify that your selected agent has been authorized to make choices for you when you are not able. please remember that for this document to be valid, the principal must be an adult who is mentally competent at the time of signing. you may choose to have your advance directive become effective immediately (even if you are still capable of making your own healthcare decisions) or to have your advance directive only become effective when you are incapable of making healthcare decisions for yourself (the latter is the more common scenario.) here are a few common situations where it might be useful to make or update your advance directive: whether your advance directive has been made as a result of a change in your health or as part of a forward-looking plan, notarization and/or witnesses are strongly recommended for protecting this document and your agent if someone challenges their privileges.