Flagstone Reinsurance Holdings, SA has announced a management shake-up which will see one of its top executives relocate from Bermuda to New York.Gary Prestia has been appointed CEO of Flagstone Representatives (US) Inc, and chairman of Mosaic NY, effective September 1, 2011. Mr Prestia will be stepping down as chief underwriting officer - North America at Flagstone Réassurance Suisse SA, and underwriting responsibilities will be taken over by three other current executives. Mr Prestia will remain a member of Flagstone’s executive committee.Flagstone, the Class of 2005 Bermuda start-up, which moved its holding company to Luxembourgh last year, added that Guy Swayne, currently chief underwriting officer - International, has been named executive vice-president of Flagstone Réassurance Suisse SA, with executive responsibility for underwriting in Bermuda as well as oversight of all international underwriting centres, including Lloyd’s where he currently serves as chairman of Flagstone Syndicate Management Ltd.David Flitman, currently chief actuary, will also assume the newly created role of executive director of Global Property Underwriting, reporting directly to Mr Swayne. In this role Mr Flitman will oversee the underwriting of both the North American and International property businesses, which are managed by Joseph Hooks and Jeffrey Franklin, respectively. Mr Hooks, currently deputy chief underwriting officer - North America, will assume the role of chief underwriting officer - North America.“Relocating Gary to New York provides an opportunity to increase and enhance our contact with our existing North American property clients and will also allow Gary to oversee the growing opportunities for our Mosaic NY operation which currently focuses on onshore energy and inland marine business,” said Flagstone CEO David Brown. “Gary has been instrumental in the growth of our North American business since Flagstone’s inception and will continue to be a tremendous asset as the company continues its growth.“This move allows Gary to be closer to our clients and to concentrate fully on growing our North American book of business and overseeing our rapidly developing Lloyds’ US underwriting platforms. We will continue to benefit from Gary’s experience, market insight, and leadership as he will remain an important participant in our high-level business strategy as well as a valuable resource on our executive committee.“We believe the changes in our Bermuda office represent significant enhancements to our operating approach, allowing more efficient oversight and management of our underwriting process. Guy Swayne has been with Flagstone since its inception and has been Gary’s partner in underwriting, with responsibility for the development of the company’s International business.“In addition to developing Flagstone’s business through his strong industry contacts, Guy has also assumed responsibility for the development of the company’s underwriting centres outside of Bermuda, most notably in Martigny, Switzerland and at Lloyd’s. Guy will continue to oversee these businesses in addition to his new responsibilities.”