Signing Requirements
An advance directive is only valid if it is acknowledged before a notary public or signed by two witnesses.[1]
Neither the health care agent nor the attending health care provider/employee can be a witness, and one witness must not be related to the declarant.
Revocation
The durable power of attorney may be revoked in any manner the principal can communicate their intent to revoke it. The healthcare provider or attorney in fact may be notified verbally or in writing.[2]
As long as the declarant can communicate, the advance directive may be revoked as long as it is communicated to the attending physician or their assistant.[3]