How to convert your windows Server 2012 R2 Evalution copy to license copy.

 

For Convert:

determine the current edition name with the command

DISM /online /Get-CurrentEdition

DISM /online /Get-TargetEditions

DISM /online /Set-Edition:<edition ID> /ProductKey:XXXXX-XXXXX-XXXXX-XXXXX-XXXXX /AcceptEula

providing the edition ID and a retail product key. The server will restart twice.

Detail info: http://technet.microsoft.com/en-us/library/jj574204.aspx