While helping his grandfather, pioneer of modern architecture Ludwig Mies van der Rohe, design IBM Plaza in the late 1960s, Dirk Lohan could hardly imagine he would be back four decades later to redesign the lobby. With others working on a 316-room luxury hotel on floors 2-13, Lohan has spent the past two years rebuilding the hotel’s ground floor lobby. It will be the first thing hotel guests see when they enter from Wabash Avenue. Now known as 330 North Wabash and soon to be renamed AMA Plaza, the 52- story building will still have a lobby for its office tenants on the north side of the building.