Hi Lilith a lot of time since you write the last time. If I remember correctly you were painting an orc army, arent you? Glad to read you again!
Concerning your question I think Geep is right.
In the situation when a cavalry win but can not pursuit (same situation as infantry vs cavalry, infantry win but can not pursuit cavalry) it is not allowed to make and advance onto other enemy unit.
But because they are won they can choose to stay there or retreat 3D6 cm, and of course, at the end of the phase as they had fought they can recolocate (realign the bases) the orientation.