Tennessee Code Title 52. Department of Disability and Aging § 52-3-102

(a) A person with an intellectual or developmental disability admitted, whether voluntarily or involuntarily, or ordered to participate in nonresidential treatment or service under this title, must not, solely by reason of the admission or order, be denied the right to dispose of property, execute instruments, make purchases, enter into contractual relationships, give informed consent to treatment, and vote, unless:

(b) A person shall not make decisions for a person supported on the basis of a claim to be the person supported's conservator, legal guardian, guardian ad litem, caregiver under title 34, chapter 6, part 3, or to be acting under a durable power of attorney for health care under title 34, chapter 6, part 2, until the person has presented written evidence of the person's status.