(a) The parties may agree on a procedure for challenging an arbitrator. A decision reached under that procedure is final.
(b) If there is not an agreement under Subsection (a), a party challenging an arbitrator shall send a written statement of the reason for the challenge to the arbitration tribunal. The party shall send the statement not later than the 15th day after the later date the party becomes aware of:
(1) the constitution of the tribunal; or
(2) a circumstance referred to in § 172.057 or 172.058.

(c) Unless the arbitrator challenged under Subsection (b) withdraws from office or the other party agrees to the challenge, the arbitration tribunal shall decide the challenge.