Tex. Rev. Civ. Stat. art. 5421c
Subsection 6b. As to any and each lease and/or contract heretofore made by the Board of Mineral Development, such Board shall be, and it is hereby, authorized and empowered to revise the same, with the consent of the lessees and/or contracting parties thereunder, their heirs, successors or assigns, in such wise as to subject such lease and/or contract thenceforth to the public policy declared in Subsection 6a. Such revision shall be accomplished by supplemental or modificatory instrument on such terms as the Board of Mineral Development may deem fair and advantageous to this State, but only after a proposal for such revision shall be formally made, in a public document, to the said Board of Mineral Development, by the lessees and/or contracting parties under such lease and/or contract, their heirs, successors or assigns; and provided that in consideration of the consent by such lessees and/or contracting parties, their heirs, successors or assigns, to such revision the Board of Mineral Development shall not reduce the State's share of the oil and/or gas to be received in the future under such lease and/or contract to less than one-fourth of the gross production of oil and/or gas from the land described in such lease and/or contract.
Provided that any revision made under this Act as referred to hereinbefore shall contain in such supplemental or modificatory instrument the power and authority on the part of the Board of Mineral Development to re-instate any money requirement or reduced royalty requirement at any time that in the opinion of the Board such re-instatement should, in view of the then existing conditions and fairness to the State of Texas under the original lease or contract, be made; and the Board of Mineral Development shall exercise such power whenever in its opinion the interest of the State of Texas requires the exercise of such power; provided, further that said Board may modify said contract as aforesaid by adjusting up or down from time to time the State's portion of said oil and/or money payment as the conditions hereinbefore set forth may justify and which may be equitable to the State and to said contractors or their assigns, but in no event shall the State's portion be less than one-fourth nor more than now provided in said contracts, and in no event shall the Board of Mineral Development have any authority to modify or change said original leases as to gas. Provided, further that no revision made under this Act shall release the lessees or their assigns from the payment to the State for any oil and/or gas produced or the delivery to the State of any oil produced and due the State under the original contracts and produced prior to the effective execution of any revision hereunder.
Provided further, that nothing in such revision shall in anywise relieve any lessee and/or contracting party from any obligation now existing to drill any well either as an offset or otherwise.
"And/or" as used in this Act shall mean and include both and either of the words "and" and "or."
Subsection 6c. No change shall be made by the Board of Mineral Development that will relieve, release and/or suspend the lessees from the payment of any money and/or royalty now due and payable to the State for oil and/or gas produced to the date that the Board makes any change in the present existing lease contracts.
Tex. Rev. Civ. Stat. Ann. art. 5421c