@SeanSunco
Assuming SDS Sharing is setup and your Cluster programming is solid then it is as simple as selecting the Secondary Element via the User and Config form.
You then would check the resilient system to make sure that the extension has been created there.
The phone may have to be reset to obtain it's resilient programming. This can be checked via the Debug mode on the phone and making sure there is an IP setting for ICP #2
You can also check the remote directory form on all systems.
Welcome to the forum SeanSunco
BTW, I'm sure if you thought long enough, you might know a KWB in the neighbourhood.
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What's most important is that you realise ... There is no spoon.