The Colorado Education Association may soon be packing up its bookbags. The state’s largest teachers union is looking to sell the building kitty-corner from the Colorado State Capitol that it has occupied for 30 years. The asking price for the four-story, 41,144-square-foot building at 1500 N. Grant St., is $6.9 million. “We learned that we can accommodate our work in a flexible way,” said CEA President Amie Baca-Oehlert.