iPhone 7+screen unresponsive and locked.

My iPhone 7+ screen is unresponsive most of the time. Sometimes it works when I warm up the phone with body heat for example. I changed the screen 3 months ago and it has a protective screen with a few scratches. I haven't updated it for a while but I cannot do that now since the iPhone is locked. I cannot connect the iPhone to my Mac. What do I do to reset the iPhone to factory settings when the iPhone screen is unresponsive and demands a code after restart.