On the 737 the call is (or certainly was) 'go around flap 15' (from normal land flap position 30, or 40), simultaneously one press of the toga switches to give reduced go-around power; or press twice if you want to get really excited! If a non normal flap 15 landing, then it was as above but the call was 'go- around flap 1'.
Years since I've flown the 777, but I believe it was the same.
kind regards
Exeng