A century-old Flatbush building, which once housed a movie palace, is looking for a new tenant to bring a renewed lease on life to the joint. The building, 1085 Flatbush Ave., now houses the Cortelyou Road Church of God, which owns the building and wants to rent out most of the 15,000-square-foot space and keep a sliver for itself. For more than half a century, the building was home to the Rialto Theatre, from 1916 to 1976. Since then, it has been the location of various houses of worship. The building …