Private First Class Pyatt was a member of Company C, 1st Battalion, 5th Marines, 1st Marine Division. On 26 March 1953, he was defending "Outpost Reno". He was listed as Missing in Action when his position was overrun by two Chinese battalions. He was presumed dead on 26 March 1954. His remains were not recovered. His name is inscribed on the Courts of the Missing at the Honolulu Memorial.

Pyatt was awarded the Purple Heart, the Combat Action Ribbon, the Korean Service Medal, the United Nations Service Medal, the National Defense Service Medal, the Korean Presidential Unit Citation and the Republic of Korea War Service Medal.