When you fail a Constitution saving throws that you make to maintain your concentration, you can expend a spell slot greater than or equal to half the level of the spell you were concentrating on (round down, minimum of 1st-level) to instead succeed on the saving throw (no action required).
If your concentration was being used for something other than a spell, such as the Trickery Domain's Channel Divinity: Invoke Duplicity feature, you can expend a spell slot of any level to succeed the saving throw.
Rule Clarification: A spell's level is equal to the level of the spell slot expended to cast it. With this feat, for example, you can use a 1st-level spell slot to maintain concentration if your concentration was being used for the spirit guardians spell cast at 3rd-level. However, if you cast the spell using a 5th-level spell slot, you would need to instead use a 2nd-level or higher spell slot to maintain your concentration.
Comments