Engineer

A model with this special rule allows a War Machine within 3" to use the Engineer's Ballistic Skill instead of its own and to reroll any rolls on the Misfire Table. (If there are several War Machines within 3" of the Engineer, declare which one will receive the Engineer's benefits this Player Turn before firing it). If the War Machine uses a Flame Thrower Artillery Weapon, all D3 rolls for the number of hits the Flame Cannon scores on its target may be rerolled.
If this is used, you must either reroll all dice or none.
This rule cannot be used by a model that is Engaged in Combat.