The character can declare that they are attempting to stun an opponent.
They then take a -1 Penalty to Attack, but if they successfully hit an opponent, the opponent loses a number of \glspl{ap} equal to half the Damage dealt (not \glspl{hp} lost).
They then take a -1 Penalty to Attack, and must have more \glspl{ap} than the opponent, but if they successfully hit, the opponent takes standard Damage, and loses a number of \glspl{ap} equal to the Knacks the character has.