I need to change the phone number for this phone. I broke my other phone and need to go back to using this phone.

You can change the number but you have to unlock the previous network your using.In case buying a new phone that also should be an unlocked phone.If not get the unlock code from the website http://www.wickedunlock.com/motorola-e815/rs11wp9/ with step by step instructions.Here you select the "supported phones" option.And you can find various kinds of mobiles in the website,from that you choose your particular phone model,give required details and get the unlock codes easy.

Take the sim out the other fone and put it in this one, if it saays incorrect sim or sim invalid, take it to a fone shop and pay to get it unlockerd