Complex sentence: He added that the matter had been raised at Wake Island, but no one else recalled this, particularly not Truman, who, unaware of these discussions, told reporters on 26 October that Koreans and not Americans would occupy the border areas.
Split into simpler sentences: He added that the matter had been raised at Wake Island, but no one else recalled it. Particularly, Truman did not recall it, and, unaware of the discussions, told reporters on 26 October that Koreans, not Americans, would occupy the border areas.