Texans won't have to. Constitutionally, the borders of any state cannot be changed or eliminated without the consent of that state's legislature and without the consent of Congress (Article IV, Section 3). California; Arizona; New Mexico; Oregon; Utah; Nevada; Colorado; Oklahoma; Kansas; Louisiana; Mississippi; Alabama; Florida; take note.
Of course a Supreme Court composed of a majority of America-haters could very well rule that that prohibition would not apply when the state is being given up to a foreign power rather than being formed into one or more other states within the US (Supreme Court followers; YOU take note). [grin]