Guided Shot
Perception Utility 6
You spot a critical weakness in afoe's defenses, which an ally can exploit to deadly effect.
Close burst 10
Trigger: An ally within 10 squares of you misses with an attack against AC
Target: The triggering ally in burst
Effect: The target's attack is made against Reflex instead of AC.
Guided Shot is an encounter power available to characters who are trained in perception at sixth level.[PH3:173]