A Durable Power of Attorney allows someone called your "Agent" or your "Attorney in Fact" to act on your behalf in a variety of situations. While a very powerful document, you should make sure it clearly spells out what your agent is entitled to do. Also, keep in mind that a Durable Power of Attorney expires when the person dies. You cannot keep using a Durable Power of Attorney once a person has passed away.
While the trustee handles all the trust assets, the agent under the Durable Power of Attorney basically handles the many other facets of a person's life.
If you'd like to learn more, please feel free to contact my office for a consultation.