A unit of troops can also change its formation by adding or reducing the number of ranks in which it is deployed. For example, a unit that consists of two ranks may increase its depth to three ranks by moving models from the front two ranks to form a new third line.
A unit must surrender half of its move to either add or deduct one rank. A unit may add or deduct two ranks if it does not move at all.
When redeploying ranks in this way it is important to remember that a unit always has the same number of models in each rank, except for the rear rank which may contain the same or fewer models. A rear rank is still a rank whether it is full or contains only one model, although only ranks of four or more models are considered to be of any value in close combat, as described later.