Tenn. Code Ann. § 8-10-117

A judge may, in writing, specially depute any discreet person of full age, not being a party to the suit pending, to perform any particular duty devolving by law upon a constable, if no constable is at hand, and the business urgent; but no judge shall make such special deputation, unless one (1) of the parties to a suit pending, or the party's attorney, shall make oath before the judge, and file the same in writing, stating that, to the best of the party's information, there is no regular officer at hand, and that the business is urgent. The person thus deputized is vested with all the powers of a constable for the occasion, and is subject to the same obligations and penalties.