Texas Government Code - GOV'T § 75.003. Assignment of Former Appellate Judge

(a) A former judge whose last judicial office before leaving active service was justice or judge of the supreme court, the court of criminal appeals, or a court of appeals is, with the former judge's consent to each assignment, subject to assignment by the chief justice of the supreme court:

(b) A reassignment by a presiding judge under Subsection (a)(2) is subject to the requirements of Section 74.055.  The assignment of a former judge by the chief justice to the administrative region of the former judge's residence continues only during the period for which the former judge has certified a willingness to serve under Section 74.0551.