College fairs, bull-riding events and graduations used to fill the arena of the Georgia Mountains Center in downtown Gainesville. Classrooms, professors and students hurrying down hallways will someday take their place, as Brenau University moves toward converting the cavernous gathering spot into the heart of its new downtown campus. “Brenau is in the business of changing lives,” Brenau President Ed Schrader said during a Monday morning ceremony recognizing the handoff of the convention center to the university.