Tex. Health and Safety Code § 121.029

(a) A health authority, unless otherwise restricted by law, may delegate a power or duty imposed on the health authority by the department, or by this or any other law, to a properly qualified physician to act while the health authority is absent or incapacitated.

(b) The physician designated by the health authority must:

(1) meet the qualifications set out in Section 121.022(a);

(2) be appointed as a designee in the same manner as the appointment of the health authority;

(3) take, subscribe, and file the official oath and appointment with the department as required by Section 121.022(b); and

(4) file a certified copy of the written delegation with the department.

(c) The delegation is effective during the term of the health authority who made the delegation; however, the health authority may limit the time to a shorter duration in the written delegation of authority.

(d) The health authority is responsible for the acts of the physician to whom the health authority has delegated the power or duty.

(e) The entity that appoints the health authority and the designee health authority must adopt procedures for the service of the designee as health authority under this section. The procedures shall prevent duplication of authority between the health authority and the designee and provide notice to the department when authority is transferred.