Complex sentence: He declined, working instead for the successful election of Ramón Magsaysay, who appointed Laurel head of a mission tasked with negotiating trade and other issues with United States officials, the result being known as the Laurel-Langley Agreement.
Split into simpler sentences: He declined, working instead for the successful election of Ramón Magsaysay, who appointed Laurel head of a mission. The mission was tasked with negotiating trade and other issues with United States officials, and the result became known as the Laurel-Langley Agreement.