(Reuters) - Boeing Co said on Friday it was separating the roles of chairman and chief executive officer to allow CEO Dennis Muilenburg to focus full time on running the U.S. planemaker as it works to return its 737 MAX jet to service. The planemaker said its decision was the latest of several actions by the board and the company's senior leadership to strengthen its governance and safety management processes."The board also plans in the near term to name a new director with deep safety..