1) Run cscript "C:\Program Files (x86)\Microsoft Office\Office16\ospp.vbs" /dstatusto get the last 5 characters of the installed product key
2) Run cscript "C:\Program Files (x86)\Microsoft Office\Office16\ospp.vbs" /unpkey:[Last 5 digits of product key]to unlicense the product.
3) Once it is unlicensed, the user can re-license Office by signing in with their HU account.