Capt. Ralph Sepulveda, outgoing commander of the Headquarters and Headquarters Company at the Army Public Health Center (Provisional) passed on his duties to incoming commander Capt. Ryan Lindell during a change of command ceremony May 16 at Aberdeen Proving Ground, Maryland.The change of command ceremony is a military tradition, enriched with symbolism and heritage. Throughout military history soldiers carried staffs and standards into battle that identified them as a unit, and unit colors marked the position of the commander on the battlefield. In the present, the colors represent not only the history and heritage of the unit, but also the unity and loyalty of the Soldiers. The colors are the commander's symbol of authority, representing the responsibility to the organization.The passing of the unit colors represents the transition of authority and responsibility from one unit commander to another. The first sergeant is the keeper of the colors, principal advisor to commander, and voice of the Soldiers. The first sergeant passed the colors to the outgoing commander, signifying his last act of allegiance to him. The colors were then passed from Sepulveda to Col. John Teyhen, APHC (P) deputy director, to signify that the unit is never without leadership, and then they were passed from Teyhen to Lindell to symbolize passing his trust and the responsibility of the unit and its Soldiers. Lastly, the colors were passed from Lindell back to the first sergeant to symbolize the confidence he has in him and the first sergeant's allegiance to the new commander.Teyhen gave a few remarks when the passing of the colors was complete, acknowledging supportive families and the loyal Soldiers."Their can-do attitude is outstanding, and they prove that organizations don't succeed on mere luck," said Teyhen. He also thanked Sepulveda for his service and great job as commander, and congratulated Lindell as the new commander.Sepulveda then gave a speech on his fondest memories from being commander and the valuable lessons he learned. He started out by saying "in every decision we make, even the ones we're not so certain about, there is an opportunity for experience that benefits the expansion of our knowledge base."He said his experience being commander was "like no other," akin to a "roller coaster ride, ups and downs, speed and adrenaline rush, very much like command."One of the lowest points was the loss of a Soldier, which "heightened [his] attention to detail and compassion, really accentuated [his] responsibilities as a new commander." Yet one of the highest points was being there with his Soldiers on the training field, a "miserably fun experience," where "the dedication and drive that these soldiers had was amazing to see firsthand."Lindell closed the ceremony with his speech and acknowledgements to the support from his family, and the honor and privilege it was to be the incoming commander."This is a duty that I will not take for granted, because I truly believe that Soldiers come first," said Lindell.He looks forward to the time he'll spend with the Soldiers and the challenges they will face."It's not just leaving an impression on others, but having an impact on others," Lindell said.