When making a conference call, a person who leaves the call will automatically be dropped...is there a specific reason you want control over manual user drops if it's as simple as the users leaving themselves? (not trying to be argumentative, seriously curious what the benefit you're seeking would be...maybe I'm missing something)
I have been on a call with two companies with a three way call before. It was a support call. One of the callers was not able to hangup on a customer. I had to end the call then call the other person back.
Nice to know I can end it.