You can expend a spell to summon monstrous allies instead, and your summoning magic is more powerful.

Prerequisite(s): Augment Summoning, Spell Focus (conjuration), 1st-level eldritch knight

Benefit: You may expend an unused prepared spell in order to cast a summon monster spell of equal or lower level to the spell you expend. In addition, your caster level for summon monster spells increases by 1.