Question : How do I deactivated Windows 2008 R2 KMS Key?

I have a Windows 2008 R2 server with a KMS key installed and activated.  I need to rebuild the machine.  How do I deactivate the Key, so that I can reactivate it after rebuilding the machine?

Answer : How do I deactivated Windows 2008 R2 KMS Key?

If you're not running your own KMS server then you're not using a KMS key, you're using a MAK.  You can't deactivate a mak, it has a certain number of allowed activations.  If your key runs out of activations you need to get a new one from microsoft.