Originally Posted by DavidO

Actually, *any* TA can book through American Express agency services... but to respond directly to your question:

(1) Your TA can follow up on your behalf with a phone call or email to the sales manager of the hotel to VIP your stay, flag your reservation for an upgrade, and convey any of your standard requests to the hotel.

(2) It saves you the hassle of dealing with FHR's website or phone system.