If you are mentally competent, you may revoke your original power of attorney at any time with a signed document.  The revocation is not effective until the attorney-in-fact has received notice of the revocation.  If you do not revoke it, a power of attorney ends at your death.  If you want your attorney-in-fact to have authority to wind up your affairs after your death, use a will to name that person as personal representative.

Also, if you get a divorce, and your spouse is your attorney-in-fact, your ex-spouse’s authority is automatically terminated.  Finally, if there is no one to serve as attorney-in-fact, the power of attorney ends.  To avoid this problem, you can name an alternative attorney-in-fact in your document.  The maker of the power of attorney may hold the original power of attorney document.  This can allow the maker to remain in control and generally results in a simple revocation.