Tenn. Code Ann. § 68-30-110: Manner of making, amending or revoking anatomical gift of decedent's body or part.

(a) A person authorized to make an anatomical gift under § 68-30-109 may make an anatomical gift by a document of gift signed by the person making the gift or by that person's oral communication that is electronically recorded or is contemporaneously reduced to a record and signed by the individual receiving the oral communication.

(b) Subject to subsection (c), an anatomical gift by a person authorized under § 68-30-109 may be amended or revoked orally or in a record by any member of a prior class who is reasonably available. If more than one (1) member of the prior class is reasonably available, the gift made by a person authorized under § 68-30-109 may be:

(1) Amended only if a majority of the reasonably available members agree to the amending of the gift; or

(2) Revoked only if a majority of the reasonably available members agree to the revoking of the gift or if they are equally divided as to whether to revoke the gift.

(c) A revocation under subsection (b) is effective only if, before an incision has been made to remove a part from the donor's body or before invasive procedures have begun to prepare the recipient, the procurement organization, transplant hospital, or physician or technician knows of the revocation.