Details, including a schedule, will be out on Monday. Source: Southwest’s 3Q2012 earnings press release:

The integration of AirTran into Southwest is our top priority and much progress was made in third quarter. We have converted nine AirTran aircraft to the Southwest livery. AirTran’s airport facilities at Seattle and Des Moines have been converted to Southwest; Key West, Florida will be converted next month; and Branson, Missouri is scheduled for March 2013. Our April 2013 schedule, to be published next week, will reflect four more AirTran city conversions at Charlotte, North Carolina; Flint, Michigan; Portland, Maine; and Rochester, New York.