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 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 manner 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 have the same or fewer models. A rear rank is still a rank whether it is full or whether it contains only one model, although only ranks of 4 or more models are of any value in hand-to-hand combat as described later.