151104-N-AT895-727 WASHINGTON (Nov. 4, 2015) Chief of Naval Operations (CNO) Adm. John Richardson attends a change of command ceremony for Naval Facilities Engineering Command (NAVFAC) and chief of civil engineers. Rear Adm. Katherine Gregory was relieved by Rear Adm. Bret Muilenburg, and Gregory retired after 33 years of service. (U.S. Navy photo by Mass Communication Specialist 1st Class Nathan Laird/Released)