Here, locate your Office application and press Modify or Change. Product Keys for Click-to-Run based installations of Office can only be modified via the command line. Office offers a scripted method to lookup your Product Key. Office and later include a vbs-script which will reveal the last 5 characters of your Product Key. The same applies to Office and Office licenses that are linked to your Microsoft Account. However, for either version there is no need to completely reinstall Office. The proper method to determine or change the Product Key depends on your version of Office or Outlook.
