Player Embed Code: Download Embed Share Mattis Attends Pacom Change of Command Ceremony Defense.gov May 30, 2018 | 9:15 Defense Secretary James N. Mattis attends the U.S. Pacific Command change of command ceremony at Joint Base Pearl Harbor-Hickam, Hawaii. Navy Adm. Philip S. Davidson takes command from outgoing commander Navy Adm. Harry B. Harris, Jr., May 30, 2018.