Do you mean capturing the received video? I believe some people are able to mirror the display to an Apple TV and record the HDMI output or if you use a Mac you can probably full screen it and also output to HDMI then record that.
This is a " breaking news situation " where the person just want to do a face time SOT "right now " . . . but the more I look at it next time I'll just shoot it "as is ' and then put it on a blue background.
The few I have seen aren't very good. Not much you can. Some type of rig that can hold your phone a light. Maybe use a lav that plugs into the phone for better sound? I have seen some crazy rigs for iPads. Maybe too much stuff to rig the phone?