You can close a PO Box by going to Manage PO Box, signing in to your account, and clicking the Close/Request Refund link next to the box. You can also request a PO Box be closed by informing the clerk at the Post Office where your box is located. Once a box is closed, be sure to submit a Change of Address (COA) form. Depending on where you close your box, the form will be provided online on your close/refund confirmation page or by the clerk at the Post Office. Your mail can be forwarded to your new address for up to one year.