PJ2,
Just for accuracy's sake, there is no "S/O" on any airliner these days, and the Captain, nobody else, calls the reject, unless it's a training situation with the training captain in the right seat. That situation calls for very clear understanding as to who will reject the takeoff and crisp cockpit discipline.
For your own accuracy, I fly for Air NZ so I should know. I'm not a Captain and I have called a reject before.
