Try an SKUUPGRADE - the eval issue can as such not be activated.
To determine the installed edition, run:
DISM /online /Get-CurrentEdition
To check the possible target editions, run:
DISM /online /Get-TargetEditions
Finally, to initiate an upgrade, run:
DISM /online /Set-Edition:<edition> /ProductKey:XXXXX-XXXXX-XXXXX-XXXXX-XXXXX
is how it works. See whether you can change from eval to standard.
But you may be out of luck - and then you may need a reinstallation.
But if it works then you MAY be lucky - if the VLK is not requiring a totally different version.
There is a reason we normally avoid installing eval versions for production.
Note to all voters to close: This is not a LEGAL advice - the poster asks about a technical implementation issue which is ok according to the board. Technically he does not ask about LICENSING (terms etc. - legal issue and VERY complicated) but how to activate his key (technical issue), and we do handle those here. Heck, for some parts of windows there are hugh guidelines for the technical side...