President Reagan tried yesterday to soothe the ruffled feelings of House Speaker Thomas P. (Tip) O'Neil Jr. (D-Mass.), whom he had offended at his press conference Tuesday.

Reagan had used the words "sheer demagoguery" to describe O'Neill's statement that the president's economic program is harmful to working people. Reagan took the statement personally and said he knew what it meant to be poor.

O'Neill responded by saying the presidential honeymoon with Congress had ended and by criticizing Reagan for suggesting that O'Neil is a demagogue.

Despite philosophical differences, Reagan and O'Neil are known for personal charm, and both displayed it yesterday.

White House principal deputy press secretary Larry Speakes said Reagan told him, "I'm going to call the speaker. He and I have had a good relationship, and I want it to continue."

Another White House aide said later that, in the phone call, Reagan told O'Neill he had not meant his statement to reflect on O'Neill personally.

O'Neill said he and the president had an "exceptionally friendly" talk.

"Politics is politics, "O'Neil said. "We may disagree during the day, but come 6 p.m. we become friends."