It's one of those things hidden in the menu you get when you drag down from the upper right (during a call). I think. I found it once on a video call to my mom,

It's one of those things hidden in the menu you get when you drag down from the upper right (during a call). I think. I found it once on a video call to my mom, but like the lost city of Atlantis, it seems to have disappeared for me again now that I'm trying to find it again. I hate the iPhone UI, but they work so well most of the time...