The USPS will send it back to you together with the new address for the recipient OR saying that they couldn't find the recipient at that address. Presumably you will write the new address in your lavender-scented address book, re-address the letter, stick on a new stamp, and pop it back in the post-box. Return Service Requested., Hello, when writing an American address do you separate City, State and ZIP Code by a comma or not. I saw it done both ways, which one is correct? Thank you., You're close: Attn. In a business letter, though, you're usually better off avoiding abbreviations, and some style guides recommend leaving 'attention' out entirely., Hi there, I hope my inquiry is not beyond the scope of this forum. I want to send a package using USPS mail service. I can't make out the following measurements in inches. It reads USPS-Produced Small Box: 8-5/8" x 5-3/8" x 1-5/8". Maximum weight 4 pounds. I wonder why there is a hyphen, Unfortunately, I have not been able to find a USPS Web site which states this clearly, and so for the moment will refer to this Web page by another source (which has links to USPS Web pages which are no longer active )., In AE, letter carriers are what used to be called - and still of are called, unofficially - mailmen (BE and at one time in AE as well, postmen). They work for the US Postal Service and deliver anything sent through the Postal Service and only things sent through the Postal Service. They are government employees. Couriers are people who work for private courier services that specialize in hand .