When someone voluntarily requests for euthanasia it means they give consent to a death-causing action. Voluntariness is morally important legally in states, like Oregon, where assisted death is permitted, because one must first voluntarily request it orally in writing. From a deontological stand point, it is immoral for one to voluntary use euthanasia as they have moral obligations to God, to oneself and the society. To God, one must not depart the life assigned to them by taking their own life without the orders of God. To oneself, self-preservation is our highest obligation and one must not abandon their humanity. To society, killing oneself injures the community and because of the social benefit one life has on others. (Fieser)
It is also legally required that only passive euthanasia is used, where a medical profession establish guidelines for treatments that can be withheld from a patient. Active euthanasia is not permitted in any state, where a third party performs an action to bring death. (Fieser) Therefore, legally,whatever a person request not ought to be done in instances where they ask for someone else to actively euthanize them.
In situations from a Neurological theory, where a person is dead if brain dead, voluntariness is not important as either a family member, a physician or a judge can decide to euthanize. One can write up a living will when they are mentally competent to decide to voluntarily euthanize under certain circumstances as to prevent others to have to make the decision or decide who has the ultimate decision. (Fieser) Morally, voluntary euthanasia is not reasonable and legally voluntariness is important when euthanasia is permitted unless the situation requires non voluntariness when a living will is not active.