https://www.raspberrypi.org/forums/viewtopic.php?f=45&t=140665&p=931876
reset_switch_RPi3_now_not_P6_but_RUN.txt

I saw some videos online adding a reset switch to the pi on P6 header pins.
I have RPi3. There is no P6, so is something like this possible?

The header position is now marked RUN

for halt-switch see DIR "Switch-On-Off-Halt-Reset"