I tried to look from the rulebook and forum but probably missed explanation what happens to defending units order tokens if he/she wins a combat?
For example if two houses (i.e. Lannister and Stark) has assigned march token (both adjacent to each other). Lannister uses the march order first and tries to occupy Starks area but loses combat thus is forced to retreat to area he came from.
Can Stark now use his march order or is it discarded after Lannister announced march to Starks area?