Help Screen won't reappear after phone use.

[Peakester]

Hi. new person here. When I use my Shift as a phone the screen shuts off )to save my brain cells) but won't reappear after I take the headset away from my face. I have to slide it open and sometimes that doesn't work either. Is there a setting I can change to just leave the screen on. I have looked online and in documentation but can't seem to locate an answer.