The remains of Air Force Lt. Col. Wendell R. Keller were found last year. He went missing in action on March 1, 1969.
Keller's name currently has a cross next to it, which represents missing veterans. His designation will be changed to a diamond, which denotes confirmed death.
A ceremony is scheduled Sunday in Washington.
Heitkamp says Keller made the ultimate sacrifice for the country and hopes the ceremony will bring some comfort to his friends and family.