ON MOTION FOR REHEARING
Appellant Rosemary Willis Roach, in her motion for rehearing, has raised three points of error. In those points, she says we erred in (1) affirming the trial court judgment because Texas law did not permit the appointment of joint managing conservators without joint written agreement on the date of commencement of this suit; (2) holding that the legislative amendments to Chapter 14 of the Texas Family Code providing for appointment of joint managing conservators without the written agreement of the parties could be retroactively applied to actions commenced before September 1, 1987, in violation of the Code Construction Act and the Texas Constitution; and (3) holding that the amendments could be retroactively applied to actions commenced before September 1,1987, since the amendments are unconstitutional if applied retroactively as ex post facto laws.
In argument under her first point, appellant simply reurges the authorities and arguments we previously set out and discussed in our initial opinion. We continue to believe our holding correct and we overrule appellant’s first point.
*33Appellant briefs and argues jointly her second and third points. We will consider and discuss them together. The thrust of her argument under these points is that for this Court to hold the amendments may be applied to a suit already pending at the time of their adoption would be to take away or impair a vested right belonging to appellant at such time. That being the case, she reasons, such an interpretation would violate the prohibition in Texas Constitution, art. I, section 16, against the enactment of retroactive or ex post facto laws. Moreover, she says, that interpretation not only violates the provision of the Code Construction Act (Tex. Gov’t Code Ann. §§ 311.001 et seq.) that a statute is presumed to be prospective unless expressly made retrospective but, because a retrospective application makes the amendments unconstitutional, such a construction does not effectuate the provision of section 811.-023 of the Code requiring that the consequences of a particular construction be considered.
The basic premise of appellant’s ingenious argument is that prior to the effective date of the amendments “both Appellant and Appellee herein were entitled to a judicial determination of sole managing conser-vatorship with the respective obligations and duties associated therewith,” and, she says, the right to appointment as sole managing conservator can hardly be classified as a mere remedy.
It is established that, although as a general rule, statutes operate prospectively, the exception, as well established as the rule, is that such statutes may operate retrospectively when that was the legislative intent, provided no impairment of vested right results. Cox v. Robison, 105 Tex. 426,150 S.W. 1149,1156 (1912). Therefore, mere retroactivity is not sufficient to invalidate a statute and retroactive laws have usually been upheld if the change is merely a change in a remedy, and condemned if the change is a change that destroys a vested right. Aetna Ins. Co. v. Richardelle, 528 S.W.2d 280, 284 (Tex.Civ.App.—Corpus Christi 1975, writ ref’d n.r.e.). In the seminal case of Mellinger v. City of Houston, 68 Tex. 37, 3 S.W. 249 (1887), the Court said:
Facts may exist out of which, in the course of time or under given circumstances, a right would become fixed or vested by operation of existing law, but until the state of facts which the law declares shall give a right comes into existence there cannot be in law a right; and for this reason it has been constantly held that, until the right becomes fixed or vested, it is lawful for the law-making power to declare that the given state of facts shall not fix it, and such laws have been constantly held not to be retroactive in the sense in which that term is used.
Id., 3 S.W. at 253.
A retroactive law does not transgress the constitutional pale unless it can be shown that the application of the law would take away or impair vested rights acquired under existing law. McCain v. Yost, 155 Tex. 174, 284 S.W.2d 898, 900 (1955). The right of appellant to be considered for appointment by the district court as sole managing conservator was not taken away or impaired by the amendments here in question. The entitlement of appellant to be sole managing conservator would not become fixed or vested within the constitutional purview until and unless she was so appointed by the court. Such an appointment, of course, had not occurred by the effective date of the amendments.
Our interpretation of the effect of the amendments would not result in the deprivation or impairment of any vested right of appellant and does not violate either statutory or constitutional limitations. Appellant’s second and third points are overruled together with her motion for rehearing.