Shares of Lyft (NASDAQ: LYFT) were on the move today after the ride-sharing operator announced a change in management. It said that the two co-founders would relinquish their roles in day-to-day operations and David Risher, a former Amazon and Microsoft executive, would become the next CEO. It was down 4% by 1:46 p.m. ET after Risher said the company wasn't interested in selling itself.