: Relating to providing for a reduction of the appraised value of a residence homestead for ad valorem tax purposes for the first tax year in which the owner qualifies the property for a residence homestead exemption based on the amount by which the limitation on increases in the appraised value of a residence homestead reduced the appraised value of the owner's former residence homestead for the last tax year in which the owner qualified the former residence homestead for a residence homestead exemption.