Thanks for your response, Idris!
At the end of my call with the Apple customer care person, she sent me an email with a link to a page of instructions on what to do if your screen is frozen or blank. I believe she understood my phone was not completely freezing nor was the screen blank. But I guess it was the closest thing to what I had explained to her was happening.
Before this most recent 15.1.1 update, I was always able to touch the green phone icon in the upper left corner and that would take me back to my phone call screen. But now when I touch the green phone icon in the upper left corner, the screen flashes and then it just stays where it is. It never takes me back to the phone call. And so I cannot even hang up the call, when the time comes.
Here are the instructions that I tried to follow and could not utilize for my phone because nothing happened when I followed the first 3 steps: the phone did not turn off. ( I know how to turn my phone off.)
Follow the steps for your device.
On your iPhone 8 or later, including iPhone SE (2nd generation)
- Press and quickly release the volume up button.
- Press and quickly release the volume down button.
- Press and hold the side button until you see the Apple logo.
- If your phone doesn't turn on, follow these steps to check your hardware and charge your phone. You might need to charge for up to an hour.
- If your phone still doesn't turn on, contact Apple Support.