Changing the Product Key for Office 2010 or Office 2013
Changing the Product Key for Office 2010 or Office 2013 doesn’t require a trip to the Registry and can be done directly from the Control Panel or via a command line.
To change it via Control Panel, open the “Add/Remove Programs” applet (Windows XP) or the “Uninstall a Program” applet (Windows Vista or Windows 7). Locate your Office 2010/2013 application and press Change. Setup will now start with the option “Enter a Product Key” which allows you to enter a different product key.
You can also change the Product Key via the OSPP.VBS script. Instead of using the /dstatus switch, you must use the /inpkey:value switch where you should replace value for your Product Key.