Chief petty officer selects prepare to receive the enlisted naval ranks most significant promotion during the CPO Pinning Ceremony Sept. 19 at the Reel Time base theatre. Chief petty officers serve a dual role as both technical experts and as leaders, with more emphasis on leadership as they progress through the CPO ranks. In the Navy, the chiefs' uniform changes to reflect this change of duty, becoming very similar to that of a commissioned officer's uniform except for different collar insignia. Another Significant change when a Sailor becomes a chief petty officer in the U.S. Navy is that from then on, they will commonly be addressed as "Chief." (U.S. Air Force photo/ Senior Airman Steven Doty)