You don’t actually move the GC between servers. Instead, you simply enable the GC on a new server, then disable the current GC. I explained how to configure a new server as a GC in the FAQ “How do I configure a server as a Global Catalog?”.
Keep in mind that if you already have one GC in the domain, you won’t want to disable that GC until after your new one has received all the existing GC content. You can check this progress by using Event Viewer to view the Directory Services log. Specifically, you’ll want to look for event ID 1119, as this figure shows, which tells you that the new server is now advertising itself as a GC server. Before event ID 1119 appears, you should see event ID 1110, which is the new server advising you of a delay (typically 5 minutes) before the new server will start advertising.
In summary, enabling a new GC is a three-step process:
If you add or remove GCs and you use Exchange Server, you must reboot the Exchange servers to let them update the DSAccess topology report and begin using the new GCs–otherwise Exchange won’t discover the GCs and use them for DSAccess. To create its AD topology view, DSAccess