While FaceTime calls are much more interactive and personal than regular old voice calls, you may find a time that you need to pause a video feed but continue talking to the person on the other end. Whether its kids running around or you need to tend to something around the house, you can easily convert a FaceTime call into an audio only call with one simple tap. When youre ready to restart the video stream, you can do that just as easily.
Heres how. via How to switch to voice only while on a FaceTime call | iMore.com.