As a safe immediate action when a foe you threaten attacks an ally, attempt to reposition or trip that foe. If successful, the foe is also sickened for 2 rounds Reflex DC 14 halves duration. You gain a +2 to CMB and DC for redirection if the foe used Power Attack or charged (+4, if both apply).
Your AoO's make foes flat-footed until the end of your next turn Reflex DC 14 negates.