Tex. Civ. Prac. & Rem. Code § 37.005
A person interested as or through an executor or administrator, including an independent executor or administrator, a trustee, guardian, other fiduciary, creditor, devisee, legatee, heir, next of kin, or cestui que trust in the administration of a trust or of the estate of a decedent, an infant, mentally incapacitated person, or insolvent may have a declaration of rights or legal relations in respect to the trust or estate:
Acts 1985, 69th Leg., ch. 959, Sec. 1, eff. Sept. 1, 1985.
Amended by Acts 1987, 70th Leg., ch. 167, Sec. 3.08(a), eff. Sept. 1, 1987;
Acts 1999, 76th Leg., ch. 855, Sec. 10, eff. Sept. 1, 1999.