Answer:
If one wishes to end a lucid dream, one simply decides to wake up while the dream is in process. If one does not want to have lucid dreams, one can reverse the method of achieving lucid dreams: before falling asleep, tell yourself that you won't have lucid dreams, but will have quiet, restful, natural dreams that will not disturb the conscious mind. If a lucid dream begins, let the conscious mind say, "No, I don't want to do this." Then move toward wakefulness without entirely waking up. (You only want to move into the next sleep cycle.) Then drift back down into natural sleep. See attached link on sleep stages.