Tips to upgrade from a mogul to diamond?

[Brett8187]

My mogul has been acting real crappy lately. Freezes alot and lags like crazy. I'm on my 3rd mogul via crashes and problems in the past not caused by me (thank god for product replacement plans). I want to switch out my phone for a diamond (for lots of reasons), any tips on how i can convince sprint to do this for me? I saw alot of people a while back switch out their mogul for a touch with no cost. My plan is also up in feburary (3 lines)

thanks guys