Could i send back and get a different phone with AT&T after 2 weeks?

we signed a new contract and i didn't really want an iphone before, but now ive come to realize the motorola flipside has VERY MANY glitches and is non-responsive A LOT OF THE TIME. it is very very frustrating and i wonder if its too late to send it back for an iphone instead without having to pay a boatload. PLEASE HELP?