If you leave enough leaf after you harvest and return to 18-24hrs lights on it will re-veg and grow again. The problem is it takes a long time to go back to veg. If you clone you can get the same thing done without the long wait.
really the latest you wana go is probably whats in the pictures above.. for a better success rate and quality id say do it as close to the veg cycle as you can (if its just started budding youll be fine and know if its a boy or a girl
but yeah as listed above just chuck it back on veg cycle and see if its too far gone. if not itle start growing again