How does one upgrade a cell phone while keeping provider and number?

First you have to log into your internet acount and push upgrade phone. They will charge you a fee if your phone is not old enough for an upgrade. --------- You can also visit any of your carrier's corporate stores or an authorized reseller. First have them confirm your eligibility to upgrade with an equipment discount. In most cases you will be eligible if you have had your existing phone at least two years, but check to be certain. (With Sprint, you can be eligible for a half-discount after only one year.) Choose your new equipment and decide on any plan changes you may want. (To take advantage of the special features of many new phones will require special plans or upgrades to your plan.) The retailer will then activate your new phone, transferring your service from the old one. (Your old phone should be turned off while the change is being made.) Your old phone will still be yours but will not be active on the service. You will keep your phone number and your voice mail, although the voice mail transfer may take a few hours. Before you make the change, however, talk to the retailer about transferring your address book entries, notebook entries, tunes, photos, and other information from your old phone to the new one. There are different means with the different providers, retailers, and phone models.