how to enter product key for publisher 2013

It's not an ideal solution but if you've got the legitimate product keys then I have found that doing an "Online Repair" of your Office package then once it has completed you are able to re-register using whatever product key you desire. I've experienced a similar problem to people here - namely, a bulk load of licenses and no way of differentiating between them or attributing the product keys to the different installs - and have found this to be the most simple way of achieving what should really be even simpler.

So, to instruct in as detailed way as possible I hope this helps people:

1. Go to Programs and Features
2. Select Microsoft Office
3. Select "Change"
4. Select "Online Repair"
5. Let the machine do its thing
6. Load an Office application
7. Select "Use a product key" - This is the important step
8. Enter your product key
9. Sign in with the Microsoft Account associated with your purchase
10. You're all set!

Please feel free to get back in touch if you have any further questions or queries!

I bet we won't receive a proper answer to  this question by Microsoft, but this is real question, and I will try anyways, even though I know it's futile. 

I am the lone support technician at our mid sized company, and can ill afford to spend hours on such a simple operation as changing the activation key for a Office 2013 install, especially when this would only took a minute or two with past versions of Office.

Please tell me why Microsoft has chosen to make such a simple task as entering a new activation key for Office 2013 so difficult and a waste of time, for anyone who has already paid the high cost of Office?

(Q.) If one wants to Change Product Key in office 2013 pro, how can you do this or do I reinstall?