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. In Hell's Angel, Sam and Dean use this sigil against Lucifer to give control of his vessel back to Castiel. This lasted for only a short while and Lucifer easily removed the sigils.