He who would be a great communicator must first persuade an audience of one, and Ronald Reagan has always listened closely to Ronald Reagan.

Trained as a performer and a persuader, Reagan is a salesman with a selective memory who conjures powerful images from the past, sometimes from a past that never existed.

Recently, historian James David Barber called my attention to a discrepancy in accounts of how Reagan formed an ambition to become an actor. Reminiscing to Hugh Sidey in the July 11 issue of Time magazine, Reagan said of his college days: "There I played Captain Stanhope in 'Journey's End.' I never was so carried away in the theater in my life. I was in the war as far as that play was concerned."

As a matter of fact, Reagan was in neither the war nor the play. He was taken by the parents of his girlfriend to see "a London touring company's production of "Journey's End." That is the account he gave me in an interview. More importantly and longer ago, it is the account that appears in Reagan's 1965 autobiography, "Where's the Rest of Me?"

This misremembered incident reminded me of another, more embroidered Reagan account. It was of his days as a football player on the high school team in Dixon, Ill., when he supposedly admitted committing an infraction of the rules that the officials hadn't detected.

As Reagan related the story to the now-defunct Rockford (Ill.) Morning Star, "I told the truth, the penalty was ruled and Dixon lost the game." There are no contemporary accounts of this incident, and no one interviewed by any Reagan biographer in Dixon recalls it.

The only varsity game in which Reagan played for Dixon was lost by his team, 24 to 0. But Reagan told and retold the story over the years as an example of the value of truthfulness, finally developing a version in his political speeches in which an unnamed player for a college team admitted dropping a pass that officials ruled he had caught.

Memory plays tricks on all of us, and Reagan's trangressions are not high crimes. It is doubtful whether many of us could survive without embellishing our childhoods. But Reagan's penchant for dramatizing an event and then remembering the imagined version as reality has persisted throughout his adult life, abetted by his career as an actor and an after-dinner speaker in which the point of an anecdote was more important than its literal truth.

When Reagan named Henry A. Kissinger to head his bipartisan commission on Central America, for instance, he seemed genuinely to believe that he had criticized Kissinger during the 1976 presidential campaign only in passing and "in response to a question." In fact, his portrayal of Kissinger as the essential architect of what Reagan regarded as a failed foreign policy was a centerpiece of his campaign and one of the main reasons it caught fire among conservatives and almost brought him the nomination against President Ford.

Few subjects are exempt from such instant historical revisionism, reminiscent of the television "docudramas" that use invented dramatic events to fill in the inevitable gaps of knowledge. Reagan remembers opposing racial discrimination but not his opposition to the Civil Rights Act of 1964. He remembers cutting the cost of government in California but not signing the largest tax increase in the state's history.

He forgets that he said, only a few months ago, that accusations about waste and inefficiency in the Pentagon were overblown and now declares "that this administration is the one that found these abuses . . . that have been going on for years."

The examples would fill not a column but a book. Reagan is a performer who persuades and governs by symbolic and evocative re-creation of the past. His ability to persuade himself that what he says is true enables him to state contrary positions with equal conviction. It also enables him to abandon untenable political positions grounded in conservative ideology without abandoning conservatism.

Reagan's ability to dramatize the past is simultaneously useful and unnerving. It is useful because it gives Reagan a way to discard unworkable ideas. It is unnerving because it requires a rewriting of history when Reagan changes his views, as he has on Kissinger, in an effort to describe his actions as consistent.

After all is said and done, the most consistent thing about Reagan may be that he remains his own best audience and that he believes what the great communicator is telling him.

Look for an important Hispanic appointment this week as the Reagan administration renews its political offensive for Hispanic votes. Reagan will hold six meetings this week with Hispanic politicians, journalists and servicemen.

First surveys for the White House show a 2-to-1 approval ratio for the president's televised speech on the Korean airline massacre. The bad news for the White House is that the surveys also show that 60 percent of Americans favor stronger sanctions against the Soviets.

Reaganism of the Week: (Speaking last Wednesday at a White House ceremony recognizing an adult literacy organization): "Hearing of some of what you've done made me ashamed of the times that I cheated in English literature on Shakespeare."