A power of attorney is an instrument by which one person (the principal) grants to another (the agent) the power to perform certain acts on his or her behalf.

The power of attorney for health care grants the agent the power to make health care decisions for the principal if he or she is unable to make them. The agent may exercise his or her authority only if the principal's attending physician certifies that, in the physician's opinion, the principal lacks the capacity to make health care decisions. The principal can revoke the power of attorney at any time, orally or in writing, and regardless of the principal's mental state. The power of attorney for health care must be signed by two witnesses, one of which is not:

1. the person designated as agent;
2. related to the principal by blood or marriage
3. an employee of the principal's health care facility who is providing direct care to the principal or who is involved in the financial affairs of the facility
4. the principal's attending physician or an employee of the physician
5. the principal's heirs; or
6. a person who would have a claim against the principal's estate upon his or her death