170915-N-JO908-139 SAN DIEGO (Sept. 15, 2017) Adm. Scott H. Swift, commander of U.S. Pacific Fleet, delivers remarks during a change of command and retirement ceremony as Vice Adm. Nora W. Tyson prepares to relinquish command of U.S. 3rd Fleet to Vice Adm. John Alexander, during a ceremony aboard the Nimitz-class aircraft carrier USS Theodore Roosevelt (CVN 71), Sept. 15, 2017. Tyson is retiring after 38 years of honorable service. (U.S. Navy photo by Mass Communication Specialist 2nd Class Kory Alsberry/Released)