Which of the following is NOT a method to request a mail hold?

The method identified as not a way to request a mail hold is accurate. Requesting a mail hold typically involves interacting directly with USPS services that are accessible to the general public, such as visiting a retail location, using the USPS website, or making a phone call to customer service.

While requesting a mail hold is often done directly by the customer, the term "agent at the post office" implies a more formal role that isn't centered on a method used by the customer. Agents are typically employees who assist customers but don't independently initiate a mail hold request without the customer framing it first.

In essence, while customers can utilize the services of retail locations, the USPS website, and phone calls, the role of an agent in this context doesn't designate a separate or independent method for making such a request. The other options are all valid and commonly used methods to facilitate the holding of mail.