May 27 (Reuters) - United Airlines Holdings Inc said on Wednesday that Jon Roitman will be replacing Greg Hart as chief operations officer effective June 1 as part of an internal management reshuffle to prepare the airline for the near-term uncertainty of travel demand.

New Chief Executive Scott Kirby announced the changes in a message to employees. Roitman is currently United's senior vice president of airport and network operations. (Reporting by Tracy Rucinski; editing by Jonathan Oatis)