Upgrade OS

I have a client who needs to upgrade their OS from Windows Server 2003 Standard Edition to Windows Server 2003 Enterprise Edition. They need to do this for some performance issues that we are working on.

I have been trying to find a document that is a “How to” kind of document for this but have not had luck. I can find some things about some gotchas on HP servers but not much else.

Has anyone done this exact upgrade? If so, how easy is it and is there any documentation that I could read about it?

Thanks for your help.