Complex sentence: The United Nations Operation in Côte d'Ivoire (UNOCI) is a peacekeeping mission whose objective is "to facilitate the implementation by the Ivorian parties of the peace agreement signed by them in January 2003" (which aimed to end the Ivorian Civil War).
Split into simpler sentences: The United Nations Operation in Côte d'Ivoire (UNOCI) is a United Nations peacekeeping mission. The aim of the mission is "to facilitate the implementation by the Ivorian parties of the peace agreement signed by them in January 2003" (which aimed to end the Ivorian Civil War).