how to activate windows 10 enterprise evaluation with MAK license

Hi,

I downloaded windows 10 enterprise evaluation. Also after testing it I purshased several licenses for it through our reseller.

If I now want to active it it gives me the error:

Searching the internet lets me believe it's possible to 'upgrade' this license to the purchased one. While some posts say it isn't possible.

However I can't find any proof othe latter...

Can somebody confirm here?