Since there would be no more thrust, they would have to exchange energy by losing altitude to keep forward speed. But what happens towards the end, when you have to reduce your V/S to something like -800/min, would a pilot for a commercial airline, flying a commercial jet, stabilize his aircraft with flaps? Or would they just drop in altitude quickly to have a high airspeed and then just let it run off by leveling out and dropping the landing gear?
Rather than put up with one us speculating and pontificating on what to do, just read this terrific account of the Air Canada Gimli Glider incident, where a '67 did exactly that. They pretty much did it right, helped by a Capt that really knew how to fly as opposed to just being competent at running the machinery.