Change your Office 2016 product key Thu, 10 May 2018 09:27
This is an excellent article by Microsoft in how to do this. I recommend the cmd line solution. I have used it successfully multiple times.https://support.office.com/en-gb/article/change-your-office-product-key-d78cf8f7-239e-4649-b726-3a8d2ceb8c81#ID0EABAAA=Use_a_command-line_script