You gain the 8th level Order Ability of the Order you selected with the Knightly Oath feat. For the purposes of using that power, treat your Cavalier or Samurai level as . You do not gain any of the other Order Abilities. You must follow your Order's edicts. If you violate any of these edicts, you lose the benefits of this feat for 24 hours. The violation of an edict is subject to GM interpretation.
If you gain levels in a class that grants the Order class feature, you can immediately trade this feat for another Combat Feat you meet the prerequisites for.