Six Flags Entertainment Corp.'s two San Antonio-area theme parks could end up on the auction block as it considers selling some of its 42 properties, Attractions Magazine reports. After completing a $261 million merger with rival amusement company Cedar Fair this summer, Six Flags is conducting a “comprehensive review” of its park holdings, which include both San Antonio's Six Flags Fiesta Texas and Schlitterbahn in New Braunfels, officials said Wednesday during an earnings call. Company officials didn't identify which parks may be most likely to end up for sale.