The first step in determining which of these two documents may control and when is to take a hard look at them both, side by side.
In some cases, they
may work together. For example, a person may name an individual to oversee medical decisions as his or her health care agent in one document—and give another person the authority to act only for financial matters in a document that may be called a power of attorney for finances.
But if you look at both documents and determine that they both direct the same thing—that they name a person to act as a heath care agent if the patient becomes unable to make personal decisions, for example—then the law will generally presume that the document completed most recently is the one that controls and that it revokes, or supersedes, the earlier one.