If I have a shot, I'll take the shot. I'm comfortable with my set up (gun, light, shooting rest, etc.) enough and ability to take the shot. That's my first answer..... Take the shot !!
There are a few variables to consider also..... how's the wind, is he vocalizing back and if so what sounds - barks, Howels, yips, none at all....... have I called this coyote before?
Most likely if I still have his attention, I'll sit silent for a while to see what he does. Time is on my side. If he hangs up out there and is barking at me, I'll back out and come back another day. (If I didn't already take the shot) Some guys may try and close the distance and move toward him. I personally don't like to do that. I'm afraid I'll spook him.
A lot of this answer is dictated by what's being played out at the time. One things for sure though, when I finish up, I'm going to give Ernie a call and run it past him for advice!!!!