I can say it no better way than the following: Rally Others does not exist. For all intents and purposes, ignore it, and any reference to it. The only models that are limited to one Rally attempt per turn are those models who are not Squad Leaders. If a Squad loses its Squad Leader, the model with the next highest leadershi becomes the de facto Leader, however, it is limited to one Rally attempt per turn. Otherwise, Squad Leaders must spend any and all Actions to attempt to Rally their Squad. Commanders may spend any and all Actions to attempt to Rally a Squad that is within Command Distance. Commanders that become the Squad Leader of a Squad are then subject to the Squad Leader rule.