CREATE TABLE table_name_83 (representative VARCHAR(255), title VARCHAR(255), termination_of_mission VARCHAR(255))
Which representative was the Ambassador Extraordinary and Plenipotentiary and had a Termination of Mission date September 20, 1996?
    
SQL: SELECT representative FROM table_name_83 WHERE title = "ambassador extraordinary and plenipotentiary" AND termination_of_mission = "september 20, 1996"