I found out that
"Upgrading from Evaluation Enterprise (a free edition) to any of the paid editions is supported for stand-alone installations, but is not supported for clustered installations."
Is it also possible to use a Volume License Key when changing to SQL Server 2012 Standard?
Is there a HowTo on the Microsoft Website?
Thanks for your Support.
You just need to perform an edition upgrade using the following article:
Hope this helps.
Microsoft is conducting an online survey to understand your opinion of the Msdn Web site. If you choose to participate, the online survey will be presented to you when you leave the Msdn Web site.
Would you like to participate?