This host is currently being managed by the vCenter Server

I have ESXi v5 installed and was testing the vCenter Server software on a standalong server and connected up to ESXi5. I later blew away the server software to test something else.

Now when I log into ESXi Server with vSphere Client I get the message "This how is currently being managed by the vCenter Server with IP address ????

How do I remove the vCenter info from ESXi so I don't receive this message?

Thanks