Acting on behalf of another person because of a signed power of attorney carries legal responsibility, so you must resign if you can't or no longer want to perform the duties. An agent, or person authorized to act for another party, can typically resign without giving a reason or waiting a specific number of days. However, you should formally notify the person you're acting for, referred to as the principal, and all other involved parties to protect yourself legally.
Draft a letter of formal resignation. Although some states don't require a letter of resignation, providing one protects you legally. Include the date the power of attorney was signed, the full names of the agent and principal, a statement that indicates you're resigning, and the last day you will act as an agent.
Take the letter to a notary public. Sign and date the letter in front of the notary and ask her to notarize your signature.
Make copies of the resignation. You need a copy for your records, copies for any other agents named in the document, and copies for all places where you had the power of attorney on file, such as the principal's bank.
Send the original resignation letter to the principal by certified mail, return receipt requested. Send copies in the same way to all places that had the power of attorney on file and the other agents. Keep your copy and the mail receipts together in a safe place.