You cannot "hang-up" on just one call. You have to let the remote party do that. All you can do is to switch to the one you want to talk to. And then switch back if you want. If you hit END it will disconnect both. This is by design -- like it or notEvery time I receive a second call while still on first call I find if I switch to call 2 I lose call 1. How do I switch from call 1 to call 2 talk a while then hang up on call 2 and return to call 1?