I'm not sure if you can at the fitting locations, but I know most golf shops will buy your trade ins.  I sold my old driver on the PGA website, and got top dollar for them and they paid for shipping!  So if they don't accept trade ins, I would try one of those methods.   Oh, and there's always the possibility that you could sell it yourself, and get more money for your club.

Titleist won't sell you clubs from their fitting locations (Oceanside and Fairhaven). You will receive your specs that they fit you for and you will have to order them through an authorized dealer. Most dealers do accept trades.