First I would like you to do a Back Up of your PlayBook using your computer and BlackBerry Desktop Software.
This can be downloaded for free from BlackBerry - BlackBerry Desktop Software - BlackBerry Software at BlackBerry.com
After the Back Up is complete I need you to unplug your PlayBook and then push and hold down the Power Button until the unit Force Powers Off.
Now, while Desktop Software is still open on your computer and the PlayBook Powered Off, Connect the PlayBook to your computer.
You should see and error screen from Desktop Software pop up that has the options to Retry, Update, or Cancel.
QUICKLY choose the Update option.
This will erase all the information off of your PlayBook and Re-Write the Software back onto it. Once it's complete your PlayBook will need to go back through the setup wizard, and you can then perform a restore using Desktop Software to return your information. The only thing that won't come back after the restore are the apps that you downloaded from App World but they can be easily Re-Installed using the My World feature in App World.
For 2, you have to do above backup and then wipe the playbook to swap BBID.
Try my first option as it usually works well.