Tenn. Code Ann. § 27-9-110: Defensive pleadings - Amendments

(a) All defendants named in such petition, desiring to make defense, shall do so by answer (in which grounds of demurrer shall be incorporated) to such petition within thirty (30) days from the date of the filing of the transcript, unless the time be extended by the court.

(b) Any other person who may be affected by the decision to be made by such court may, upon leave given, intervene and file such an answer in the cause.

(c) Amendments may be granted as in chancery procedure.

Code 1932, § 9013; T.C.A. (orig. ed.), § 27-910.