https://techcrunch.com/2018/12/05/you-can-now-once-again-flip-the-camera-during-facetime-calls-with-just-one-tap/

With the release of iOS 12, Apple hid the button that lets you jump from front camera to rear camera (or vice versa) during a FaceTime call. Previously a one-click thing, it was suddenly shoved away into a menu as if it wasn’t something you might use a half-dozen times per call.

Don’t like the change? Good news! Apple is undoing it.