Way 3: Change Office Product Key using Command Prompt.
Way 2: Change Installation to Change Product Key.
Way 1: Remove Product Key from the Files Menu.
These methods do not require you to re-install the Office suite on your computer. Here’s a short guide that gives you 3 ways to change the Office 2016/2013/2010 product key on your computer. Also, Microsoft always recommends using genuine keys for best support. While you don’t have to change the product key of Office 2016/2013/2010 most of the times, but if you had entered a pirated key to activate and later on you bought a key from a genuine supplier, you might want to update the key so that it reflects the newer and purchased one.