This older hint showed you which files to remove to change the Microsoft Office 2004 Personalization values.
An easier way to do this is the lauch the Remove Office application in the Additional Tools Folder in your Microsoft Office folder. After you lauch the application, hold the Option key down. The Continue button will change to read "Remove License Info Only." I haven't tested this with Office v.X, however.
Mac OS X Hints
http://hints.macworld.com/article.php?story=20060927084052946