A federal law will force changes at an alternative school program for teenagers dealing with homelessness, family conflict, and mental health issues. The education program at Crosswalk, a downtown emergency shelter, works with about 70 students. About 20 to 30 of the students in the program are homeless, said Marilee Roloff, founding director of Crosswalk and CEO of the local Volunteers of America, the nonprofit that oversees the shelter. Crosswalk's education program has been operating for more than two decades.