Ronald Reagan was the 40th President of the United States, serving from 1981 to 1989. During his presidency, he held the title of Acting President on two occasions. The first time was in 1985 when he underwent surgery for colon cancer and Vice President George H.W. Bush assumed the role of Acting President. The second time was in 1987 when Reagan underwent a minor surgical procedure and Vice President Bush again assumed the role of Acting President.