Can i trade in my iphone5 to get the iphone5s?

I have AT&T and i just got my phone probably 3 months ago and i didn't realize they were coming out with a new iphone until now. I was wondering if i could do some type of trade in value or maybe sell my phone back to them and just pay the difference for the new phone. Any respond will help thanls xoxox

Of course, you can change old to new to Apple Store.

You can switch but it will cost a lot of money.

iPhone 5S with no contract:
16GB - $649
32GB - $749
64GB - $849