Your new PIN will be updated on the BES after you activate again.
If you use the switch device wizard in desktop manager all of your data will be already installed on your device before you try to re-activate.

Other than that, unless you are restricted from activation somehow, there won't be any difference.

If you use BIS e-mail as well you will need to login and update your new PIN of your device and push your service books again.

If you are on a BES, that means its a device used for work. I would check with your IT department that you are allowed to activate a new BB.

Cheers.