How to split conference call into private

If I understand you correctly your want to make a conference call private by removing one or more persons from the call. If I am right then --> The link on top of this page, under the "Related Article” is the process. If that link did not help then please mention the exact difficulty faced by you.

You probably missed the section How to remove someone

1. While on a conference call, tap the Info button .
2. Tap End next to the person that you want to remove.

If you don't see the option to remove a caller, the current call or your carrier might not support it.

If you find something is missing on iOS devices, you may provide --> Feedback - iPhone - Apple < here.