John Ambrose, chief operating officer of Rentech Nitrogen GP LLC, the general partner of Rentech Nitrogen Partners LP, notified Rentech Nitrogen Jan. 5 of his intention to retire effective Jan. 9, 2015. Following his departure, Rentech Nitrogen will eliminate the position of chief operating officer as part of a reorganization of its management structure. John Diesch will continue overseeing day to day operations in his capacity as president of Rentech Nitrogen, with the plant managers at the LP’s East Dubuque, Ill., and Pasadena, Texas, facilities reporting to him.