Sepulchral Sublimation
FEAT 14 1 action
ability to permanently create or control undead; cleric with a negative font, oracle of bones, or necromancer wizard
You have at least one undead minion that you permanently control.
You repurpose the void energy that flows through your minions at a moment's notice. Instantly destroy one undead minion within 60 feet that is permanently under your control. If your next action is to cast a necromancy spell from a spell slot, you don't expend the slot. The spell's rank must be half the destroyed minion's level or lower and the spell can't have a duration.
This feat has the trait matching your spellcasting tradition.
Pathfinder Book of the DeadOGL