Schedule Redelivery of your Letter
If the USPS was unable to deliver your letter on the first attempt, you can schedule the redelivery of your letter on the USPS website. You must enter your tracking number where it says "Track Your Package" and fill out the information under "Schedule Redelivery".
The USPS should then attempt to redeliver your letter again.
Note: This option will only be available if your letter is eligible for the redelivery according to the USPS.