How to get rid of iMessage receive number?

My phone broke, so my sister decided to temporarily use the plan on her iphone 4 until i got my phone fixed. When i got my phone back, i noticed everyone with an iphone that sent me messages would get to her iMessage. It's still set to receive my number. How could i remove that without resetting the phone, as she does not want to do that.

Go to settings, messages and then scroll down until you see send and receive and click what numbers you want on or off.