Tenn. Code § 66-21-111
In any county having a population of not less than thirty-two thousand six hundred (32,600) nor more than thirty-two thousand seven hundred (32,700) according to the 1980 federal census or any subsequent federal census the record of liens so provided may be released by the plaintiff, complainant, lienor or owner of the lien, or such person's attorney of record, entering in the blank space under the record of such lien the words "Released in full," or their equivalent, dating and signing the same, which entry shall be witnessed in writing on the record by the register or the register's deputy, for which service the register is entitled to a fee of three dollars ($3.00) to be paid by the lienor, unless the contract provides otherwise.
T.C.A. § 66-21-111