In general configuration settings are here:

[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon\CMGshield]

Here are the locations for your particular updates:

[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon\CMGshield]

"Server"="SERVERHOSTNAME"
"GK"="POLICYPROXYHOSTNAME"

[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon\CMGshield\Servlet]
@="DEVICESERVERURL"

As a warning please be careful, if you switch what server the endpoint is pointing to it could cause unexpected results with recovery and status of the machine in the server console.

Additionally they need to keep in mind that the POLICYPROXYHOSTNAME can be overridden by policy.