A personal telephone call from the president's daughter led last week to an unusual meeting between Ronald Reagan and a man of his generation who opposes almost everything he stands for in dealing with the Soviets.

The meeting is unlikely to have any direct impact on U.S. foreign policy. But it provided an unusual glimpse of how Reagan responds as a father and of the respect he shows for his youngest daughter despite a profound difference on political issues.

Patricia Ann Reagan, better known as Patti Davis, is no patsy. She is a bright, dedicated young woman who worked last November on behalf of the nuclear freeze initiative on the California ballot that her father hoped would be defeated. One of her friends and fellow freeze supporters is Michele Willens, a young California writer and daughter of Harold Willens, a wealthy peace activist who organized businessmen against the Vietnam war and now makes reduction of nuclear weapons his No. 1 priority.

After the freeze measure was approved with the votes of 3.8 million Californians, lame-duck governor Edmund G. (Jerry) Brown Jr. signed a letter conveying its message to the president, as required by the initiative.

Sen. Alan Cranston, the first officially announced Democratic presidential candidate, wanted to deliver the letter personally to Reagan, a request never taken seriously at the White House, where it was regarded as a rather transparent political ploy. In addition, Reagan does not care for Cranston, who called him an "extremist" in the 1966 California gubernatorial campaign and tried unsuccessfully to link him to the John Birch Society.

But Willens, whose devotion to the cause of peace is respected even by those who think him naive about Soviet intentions, is a different story. He is well-connected in southern California and, at 69, is only three years younger than the president.

Willens told skeptical friends that he was determined to see the president personally and asked his daughter to enlist Patti in the campaign. After a series of telephone conversations that also involved deputy chief of staff Michael K. Deaver, Willens wound up in the Oval Office last week chatting with the president.

The meeting did not change anyone's views. Willens, who supports a bilateral, not unilateral, freeze, told Reagan that he enthusiastically backs the administration's arms control efforts at Geneva through the process known as START. "But before we start START, we have to stop what we've been doing for 37 years," he said.

"Yeah, but the problem you and your friends don't understand, Mr. Willens, is that the Soviets are way ahead of us," Reagan replied. "We've got to catch up and then freeze."

Willens politely disputed this view, then suggested that Reagan and Soviet leader Yuri V. Andropov should meet in Hiroshima to symbolize their mutual desire to avoid nuclear war. Reagan, with equal politeness, said he would think about it. The two parted with Willlens saying, "Thanks for not chopping off the messenger's head."

It is clear from Willens' account of the friendly meeting and from Deaver's that Reagan is not about to go soft on arms control. But Willens was left with the impression that the president is truly listening, and other straws in the wind support this opinion. Only a few weeks ago, for instance, Boston anti-nuclear activist Helen Caldicott, head of Physicians for Social Responsibility, spent 45 minutes in a private meeting with Reagan at the White House going over some of the same ground that Willens covered last week.

The Caldicott meeting also was arranged because of a call by Patti, who has the ear of her influential father. One hopes that it isn't the last call she makes to the White House.

The Willens meeting, incidentally, angered several reporters not told about it, and their ire was misdirected at the White House press office, which again was not clued in on what was happening. The president has a right to private meetings but, as White House spokesman Larry Speakes subsequently observed, a meeting isn't private when attended by a Los Angeles Times photographer. In this case, Deaver said he takes responsibility for not informing the press office in time. Dialogue of the Week: During a meeting with out-of-town editors last week, Don Mulford of The Montclair (N.J.) Times asked the president: "Do you feel that 'The Winds of War' is helping you keep the defense budget from being cut? "

Answered Reagan: "You know, I asked somebody, having looked at a couple of installments of that myself, I said--do you suppose that this could be a help to us because it reminds us of how blind so much of the world was to the threat that many years ago? And, of course . . . more than half the population of our country today was born after World War II. So it is kind of like the Civil War must have been when I was born." Reaganism of the Week: From a meeting with local television anchors last Monday, "I know this thing about supposedly our tax program is for the rich. I've never been able to figure that out."