Tex. Occupations Code § 351.265

(a) The board by rule may allow a license holder to place the person's license on retired status. A license holder must apply to the board for retired status, on a form prescribed by the board, before the expiration date of the person's license.

(b) In determining whether to grant retired status, the board shall consider the age, years of practice, and status of the license holder at the time of the application.

(c) A license holder on retired status:

(1) must pay a license renewal fee in an amount equal to the renewal fee for a license on inactive status; and

(2) except as provided by Subsection (f), may not perform any activity regulated under this chapter.

(d) To reinstate a license placed on retired status, the license holder must submit a written request for reinstatement to the board. The board may return the license to active status and issue a renewal license if the license holder complies with any education or other requirement established by board rule and pays the renewal fee in effect at the time of the requested reinstatement.

(e) The board may charge a reasonable administrative fee to cover the cost of research and the preparation of documentation for the board's consideration of a request for reinstatement of a license on retired status.

(f) A license holder on retired status may perform an activity regulated under this chapter if the license holder's practice consists only of voluntary charity care, as defined by board rule. The board's rules under this subsection must prescribe the scope of practice permitted for the license holder, the license holder's authority to prescribe and administer drugs, and any continuing education requirements applicable to the license holder. The scope of practice of a license holder on retired status may not be greater than the scope of practice of the same license holder on active status.