It had all the trappings of just another press conference, but it was really a changing of the guard, as Ralph P. Davidson, a publishing executive with Time Inc., was yesterday named heir apparent to Roger L. Stevens, Kennedy Center chairman.

Stevens, 77, fought for years to create the center and has been its guiding force since its opening in 1971.

Davidson, 59, will take over as the center's president and chief executive officer on Feb. 1, when he retires from Time Inc. On July 1, he will also become the center's chairman.

The official announcement was made in the Opera Tier Lounge minutes after 20 of 21 members of the center's board of trustees, acting on a recommendation of a longstanding search committee, voted to confirm Davidson's contract. It calls for a yearly salary of $125,000 and includes such perquisites as a car and chauffeur and moving expenses from New York City, where Davidson currently resides.

Davidson's contract is for three years and is automatically renewable. It can be canceled by either party with a year's notice.

"There are a lot of tears around here," said one Kennedy Center worker as the news of Stevens' eventual departure traveled through the building.

Historian and former librarian of Congress Daniel Boorstin confirmed reports that he cast the single dissenting vote. Contacted late yesterday, Boorstin said, "It is a fact and I am glad to explain it. There is nothing personal in all this. I have a high regard of him {Davidson} from all I've heard.

"The point I was trying to make is that the cultural institutions stand for things that are substantive, not mechanical and administrative. I would be happier to see the Kennedy Center in the hands of someone distinguished in the performing arts rather than someone with administrative and business talents. Of course, money-raisers are important, but the tendency these days is to put them at the top and that gets things upside down."

Conceding his lack of theatrical experience, Davidson shied away from questions regarding the future of the institution he will head, other than to say that his goal is "to make the Kennedy Center the nation's leading arts center." He called his new position "the most exciting challenge someone with my background could possibly have" and said his first assignment was "learning how this place works."

On further questioning, Davidson allowed that a $50 million endowment for the center would also be a "high priority."

The board also voted yesterday to give Stevens the title of founder/chairman. He will hold it "for as long as he chooses, for the time of his natural life, which we hope is another 30 years," said Jack Valenti, president of the Motion Picture Association of America and a center trustee.

Both Stevens and Davidson emphasized that they would have a close working relationship, at least in the early months of Davidson's tenure.

"I have a lot to learn before changing what is a highly professional, very well-run center," said Davidson. Asked what he thought was the biggest challenge facing him, he said, "to do a better job than he {Stevens} has done and that's not going to be easy. From my point of view, I hope Roger doesn't go fishing for too long."

Stevens does not fish, but he expressed his desire "to be as helpful for as long as possible." He refused, however, to enumerate those qualities that had made Davidson his successor. Davidson's record spoke for itself, Stevens said, with a characteristic grumble.

Yesterday's announcement capped a two-year search for Stevens' replacement. With it came the slow-dawning realization that the Stevens era -- a one-man show that has alternately thrilled, amused, bewildered and enchanted members of the Washington arts scene -- was coming to an end.

"What we wanted was a Roger clone," conceded one trustee. "But that doesn't exist."

Last year the position was offered to Beverly Sills, who turned it down. Eventually, more than 100 candidates were considered for the post, some identified by the Los Angeles headhunting firm Heidrick and Struggles. Davidson, a dark horse, began emerging early this year after Stevens brought his name to the attention of the search committee.

Davidson has spent 33 years with Time Inc. -- 21 of them in executive positions. Up to now, he has had only tangential experience with the arts, as a member of the board of directors of the New York City Ballet and chairman of the Business Committee for the Arts. He claims some familiarity with arts operations through his involvement with Time Inc.'s Home Box Office.

Boorstin's objections notwithstanding, Davidson's administrative abilities and his fund-raising expertise were apparently deciding factors with most of the trustees.

"Running a magazine is show business, too," said Stevens gallantly.

If Stevens showed relatively little emotion yesterday, many of the center's staff were visibly upset. Several wore long faces and shook their heads, despite Davidson's repeated praise for their efforts. "You know Roger," said Charlotte Woollard, a longtime assistant to Stevens, choking back tears. "He's been with this place since it was just a hole in the ground. Every Saturday he's in the office, and Sundays, too. What's he going to do?"

She was immediately consoled by friends saying, "It's just awful," and "We feel the same way you do."

As for his future, Stevens was vague. "Believe it or not, I haven't really given it a lot of thought. I get tired a lot more easily these days. I suddenly woke up and realized I'd given the last 25 years of my life to this place."

He said he might produce more plays with his New York commercial partner, Robert Whitehead. Then with a wry smile, he quipped, "I'm just a mass of impenetrability today."

By contrast, Davidson, attired in a dark navy suit and red tie, was a picture of smooth confidence. "If I were daunted, I wouldn't be here," he said.

Accompanying him was his wife Lou, who said she was looking forward to "playing whatever role I can play -- as helpmate, as hostess or as volunteer. The Friends of the Kennedy Center {a volunteer support organization} is just an amazing group." The Davidsons have four children, two boys and two girls, ranging in ages from 18 to 2. The family plans to move here by Feb. 1.

Davidson said he has attended the Kennedy Center "about half a dozen times" and generally goes to a cultural event in New York "about once a month." He described his tastes as "catholic. I just went to see Neil Simon's latest play {'Broadway Bound'} and it was great fun." He also said he had recently caught comic Jackie Mason's one-man show, "The World According to Me."

"I wish we could get him to play the center," Davidson said.

"We could," quickly replied Stevens. "Nick Vanoff's the producer." (With George Stevens Jr., Vanoff produces the annual Kennedy Center Honors.)

As the center's chairman, Stevens received no salary over the years and often said he considered the position a "public service job." Davidson, whose early retirement package with Time Inc. is reported to be worth more than $4 million, was asked if he had considered taking the job on similar terms. "My retirement with Time Inc. is between me and Time Inc.," he said. "I do consider this a public service job. The trustees are looking to the future to establish the Kennedy Center on a professionally managed basis. I'm the first of that generation."

As the Davidsons were leaving the center by a back corridor, they encountered several male dancers from the Bolshoi Ballet, garbed in caveman skins.

"Are these my new neighbors?" asked Lou Davidson.