Can I trade in my iPhone 5s for a 5c?

I recently got the iPhone 5s for my birthday last month but it's not exactly what I wanted. I wanted the 5c, my phone has a warranty on it. So if I take my phone in and say it has "water damage" or something and ask to trade it in for a 5c would they let me?

No, plus they actually do tests to find out if anything is wrong with it. If it needs a replacement then they will replace it with the same model. What's wrong with the 5S? It's actually better than the 5C, I'm guessing you wanted the cheap colourful casings that the 5C offers.

Sure they would take it and then you would have to pay for a new 5C. They would give you a little credit for the water damaged phone, but value goes way down to due to water damage.