1. Verify with this command that DC hasn't any 5 AD Role (cmd executed as Administrator):
netdom query fsmo
2. start --> run --> (executed as Administrator) DCPromo
2008 Server - Remove a Windows Server 2008R2 DC from an existing domain
2008 - How to demote one domain controller from an existing domain
If you have different domain controller and you need to dismiss one you can follow this procedure:
1. Verify with this command that DC hasn't any 5 AD Role (cmd executed as Administrator):
netdom query fsmo
2. start --> run --> (executed as Administrator) DCPromo
1. Verify with this command that DC hasn't any 5 AD Role (cmd executed as Administrator):
netdom query fsmo
2. start --> run --> (executed as Administrator) DCPromo