Angel Suppressing Sigil

An angel suppressing sigil can be used to give control of a vessel to the human the angel is inhabiting. Unlike angel banishing sigils, it need not be drawn in blood, though it needs blood for the spell to kick in. Once activated, the sigil will briefly weaken the possessing angel's control, giving control to host. However even the slightest alteration to the sigil will render the spell useless.

When Castiel tells Dean that the angel Ezekiel died during the fall, Dean tasks Kevin with finding a spell that would "power down" the angel so he would not be in control.