@Suresh Ramasamy
Hi,
Yes, you can.
For details, including important caveats and limitations on upgrade, license conversion between editions of Windows Server 2012 R2, and conversion of evaluation editions to retail, see Upgrade Options for Windows Server 2012 R2.
https://learn.microsoft.com/en-us/windows-server/get-started/installation-and-upgrade#upgrading-to-windows-server-2012-r2
Hope above information can help you.
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