In Central Power & Light Co. v. Sharp, 960 S.W.2d 617, 618, 40 Tex. Sup. Ct. J. 443 (Tex. 1997), the district court dismissed CP&L's declaratory-judgment claims because CP&L failed to exhaust its administrative remedies before bringing its tax refund suit in district court--more specifically, CP&L failed to challenge the constitutionality of a statute in its motion for rehearing before the Comptroller. Id. The supreme court held that, because agencies lack the authority to declare the constitutionality of a statute, CP&L's failure to raise its constitutional claims in the motion for rehearing at the agency did not prohibit the district court from considering that claim when raised for the first time in the refund suit. Id.