A more thorough explanation:

An advance directive is a legal document that comes into effect when a person is unable to make decisions due to illness or incapacity. It is a way for individuals to communicate their wishes about medical treatment and end-of-life care.

There are different types of advance directives, including:

• Living Will: This document outlines the medical treatments a person wants or does not want if they become unable to communicate their wishes. For example, a person may state that they do not want to be kept alive by artificial means if they are in a vegetative state.
• Healthcare Power of Attorney: This document designates a person to make medical decisions on behalf of the individual if they are unable to do so. For example, a person may name their spouse or adult child as their healthcare proxy.

Each state has its own laws regarding advance directives, so it is important to consult with an attorney or healthcare provider to ensure that the document is legally binding.

For instance, in New York, an advance directive is defined in § 400.21 of the Public Health Law. This section outlines the elements that must be included in the document, the purpose of the directive, and the legal requirements for it to be valid.

Overall, an advance directive is an important tool for individuals to ensure that their wishes are respected and their medical care is in line with their values and beliefs.