Ive never done this before so I thought I might ask before I do it. I have a user that got a new BB 8700. Hes currently has a BB 7250. My question is on the BES Manger how do you swap phones? Do I delete him and create him again? Anyone can help. Prolly easy others but just want to make sure.

No need to remove/readd on the BES. What version of BES do you have?

If 4.x, just set a new Enterprise Activation password for him and he can perform the activation on his new device.

If not 4.x, have him connect the device to his PC, start up Desktop Manager, and when asked if he wants to switch to the new PIN, have him click Yes. He may also have to use IntelliSync to sync the new device with his Outlook account (we've had 4.0 for a year and a half, so I can't remember for sure).