Answer: Windows Server 2008 introduces a new feature that allows us to upgrade the O/S version from Standard edition to Enterprise edition without the need to rebuild the O/S from scratch.
The entire operation can take 10 minutes.
Remember: You can’t do a backward upgrade (from enterprise to standard).
The operation for Windows Server 2008 or R2 version is the same, just remember to use the correct installation media.
To upgrade Windows Server 2008 from Standard Edition to Enterprise edition follow the steps below:
Insert the Windows Server 2008 or 2008 R2 Version to the Server DVD rom
(If using R2 you can only use R2 media for the upgrade) and start the installation wizard:
In the installation wizard click Install now:
Select if you want to check for updates before or not (I didn’t select that).
Select the O/S version you want to upgrade to.
Wait for the files to be copy, and note that the server will reboot for 10 minutes.
After reboot the will start, with the new version.