Those over the age of 18 are allowed to have a healthcare proxy, and these documents are useful in situations that render a person unable to communicate their wishes such as being in a persistent vegetative state, having a form of dementia or an illness that takes away one's ability to effectively communicate, or being under anesthesia when a decision needs to be made. Healthcare proxies are one of three ways that surrogate decision makers are enacted, the other two being court orders and laws for the automatic succession of decision makers. In contrast to a living will, healthcare proxies do not set out possible outcomes with predetermined reactions, rather they appoint someone to carry out the wishes of an individual.