iphone x hang up a call

2 questions on using the new iPhone X.

1) How do you hang up a call without shutting off the phone with the sleep button? If you leave the phone section to go into another App and then return to the phone call, the Red phone symbol to hang up the call is not there. It is the Green call button instead and pressing it does nothing. See screen shot below. That photo was taken while on a call and there is no Red button to press to hang it up.

2) How do you switch to the speaker phone mid call after leaving and returning to the phone App? Again, you are at the screen shown in the screen shot below and want to get to the speakerphone; no option to get there that I can see.

Appreciate any assistance.

Mark