Windows Server In-Place Upgrade

This will help you when you rely on others to build you a server running Windows Enterprise and they install Windows Standard instead.

This will also help you if that machine is virtual as you can do this remotely.

What you first want to do is grab the product key of the host. If you don't have it handy you can grab it from the current host by using a Product Key Finder.

After getting your Product Key key you are ready to perform your In Place Windows Server 2008 R2 Standard to Enterprise Upgrade