N.C. Gen. Stat. § 44A-24.6: When lien claim release or satisfaction to be filed.

If a claim for a lien has been filed with the clerk of superior court and a condition occurs that would preclude the lien claimant from receiving compensation under the terms of the written agreement for broker services on which the lien is based, the lien claimant shall file and serve the owner of record a written release or satisfaction of the lien promptly, and in no event more than 30 days after the demand. (2011-165, s. 1.)