Yes it is possible to perform with no strange tools at all. Before you start you need to have your product key (either a MAK or a KMS client key)
- Start an elevated command or powershell prompt.
- Execute “slmgr /dlv” to get information on the current status.
- Execute “dism /online /get-currentedition” to get the current edition, it should be an Evaledition
- Execute “dism /online /set-edition:ServerStandard /productkey:D2N9P-3P6X9-2R39C-7RTCD-MDVJX /accepteula”
- The key in this case is the KMS Client key for Windows Server 2012 R2 and you can get all those keys from
- Restart the server (it will reboot twice)