Complex sentence: William McCormick Blair, Jr. (b.1916-still living as of 1991) was a lawyer and close associate of Adlai Stevenson, who served as the US Ambassador to Denmark from 1961 to 1964, and Ambassador to the Philippines from 1964 to 1967.
Split into simpler sentences: William McCormick Blair, Jr. (b.1916-still living as of 1991) was a lawyer and close associate of Adlai Stevenson. Blair served as the U.S. Ambassador to Denmark from 1961 to 1964, and U.S. Ambassador to the Philippines from 1964 to 1967.