Hi Jim,
You can use the following KB (VMware KB: Replacing a Windows 2008 Server with vCenter Server Heartbeat installed ), if you plan to replace the physical server with another physical. If you want to use a VM instead, you can just clone it and do the configuration to change its identity to the correct one.
As this KB is older, you will also have to rename the "new" server.
1. with the NICs disconnected, rename it to the name of the replaced server (i.e. primary management name) and add it to a workgroup.
2. after the machine is renamend, connect the NIC and add it back to the domain with the correct management name