Tenn. Code § 52-5-106
A person with an intellectual or developmental disability, a parent or legal guardian of a child with an intellectual or developmental disability, a conservator of a person with an intellectual or developmental disability, the department of children's services on behalf of a person in its legal custody who has an intellectual or developmental disability, or the department of human services on behalf of a person in its legal custody who has an intellectual or developmental disability, referred to as the applicant, may apply to the department through its designated entities for services and supports that they provide directly or by contract. The designated entity shall inform the applicant about all options for services and supports. When services and supports appropriate for the applicant are not available, the designated entity must notify the applicant in writing of the basis on which the decision was made, possible service options, the prospects for obtaining service, and the time estimated before the service may be available. The applicant must be notified periodically and in a timely manner of the status of the application. Based upon additional information, change in status may be determined by the designated entity.
T.C.A. § 52-5-106