New floor plans and renderings suggest that Atlanta's oldest skyscraper — a Neo-Classical icon from 1897 — could soon waltz into the 21st Century like an IT whiz hipster who appreciates a smart cocktail. Billed as the "Epicenter of Downtown Revitalization," the transformation of the 11-story Flatiron Building into an entrepreneurial hub has already snagged future tenants such as Microsoft — they'll build an "innovation center" inside — and a new Women's Entrepreneurship Initiative. But the $12 renovation project also calls for a lounge and food hall on the ground floor — with a bar built into the basement's old bank vault. Elsewhere, flexible office spaces are being configurated to capitalize on views of Woodruff Park and "pedestrian vitality" on Broad and Peachtree streets, developers say. Reservations will open soon for what's being touted as "sophisticated space that reflects the way you work."