"Once per turn, during your Battle Phase (except during the Damage Step): You can target 1 monster you control; change its battle position, and if you do, switch its current ATK and DEF until the end of this turn." effect is an optional Trigger Effect. (This effect targets 1 monster you control. It cannot be activated during the Damage Step.)
If the ATK or DEF have been modified by the effect of an Equip Spell Card, the modified values are switched until the end of the turn.