As long as you are sound of mind, you can change your medical directive at any time. You can even cancel it entirely if you wish. Be sure to alert your family, health care providers, power of attorney, and anyone else you choose that you’ve made changes.
Can medical professionals refuse?
Though directives are legally recognized documents, you should know that medical professionals can still refuse to comply with your wishes. If they find your instructions medically inappropriate or unconscionable, they can refuse to follow them. However, they do have an obligation to help find another provider that can and will comply with your directive.