Reset license key for MS Mac Office 2011

I need to enter a new MS Office for Mac license key.
How can I reset my old one?

Solution 1:

From this forum post:

Ditch /Library/Preferences/com.microsoft.office.licensing.plist. Start any Office application. Reregister/reactivate.

Hope it helps.

Solution 2:

To add to this, once you delete /Library/Preferences/com.microsoft.office.licensing.plist you then need to reboot. The activate office screen will then come up when you open any Office app.

Solution 3:

This does not work if you switch computers, Office will complain that product has been used the maximum number of times.

One has to call them to reset activations.