Soon after leaving the visible post of Congressional Budget Office director in 1983, Alice Rivlin was on a plane to New York when she noticed a seatmate eyeing her quizzically. "Didn't you used to be Alice Rivlin?" he asked finally.

"I think I still am," Rivlin replied.This weekend, hundreds of senior officials across Washington knew that feeling well. Cabinet secretaries, deputy assistants, assistant deputies and many more simultaneously were toppled from title-dom and dropped into the cold, cruel Outside - that world without schedulers, without drivers, without dinners being thrown for them, favors being asked of them, traffic being stopped for them, seats being saved for them, excuses being made for them.

So, to all those has-beens out there, this one's for you. Here are tales from those who took the plunge - and lived to tell the story.

Stuart Eizenstat, President Carter's domestic-policy adviser, planned a trip to Israel to ease his re-entry. Days after Carter left office, private citizen Eizenstat was driven by his wife, Fran, to 14th and K streets, where people who don't have diplomatic passports get their travel papers.

"I forgot for a minute that this wasn't the White House car dropping me off," recalled Eizenstat, now head of the Washington office of an Atlanta law firm, "and so I said what I'd said for four years when I'd been dropped off: `Just circle around and find a place and I'll be out in half an hour.' And Fran said, `Buster, you are on your own. Take the Metro home.' "

Charles Schultze was scheduled to speak at a conference in Philadelphia the day after leaving office as President Johnson's budget director. In the administration, Schultze had an assistant who typed his schedule on a small card and presented it to him daily. On that morning after, he boarded a train and arrived in Philadelphia, only to discover he was cardless.

"I got off the train and I realized I didn't know where I was going, or even whom to call," Schultze recalled. All he knew was the name of a New York group sponsoring the meeting. "I called the outfit in New York, got their headquarters and shamefacedly told them I didn't know where I was going."

More recently, John Gavin, ambassador to Mexico from 1981 to 1986, was rushing to his first black-tie party after his return to private life. He jumped into the back seat of his car - only to realize there was no driver in front.

Former Defense Secretary Caspar Weinberger, with military jets no longer at his disposal, has been shocked by the travails of commercial air travel. "They seat me next to people I don't even know," he has told friends.

His colleague, former Navy Secretary John Lehman, also finds the world of airplanes "horrifying," but his wife was more worried about his re-entry on the ground. For his welcome-to-the-real-world pres-ent, she gave him a Sears Roebuck driver's training course. (Lehman, a driving enthusiast, has four cars.)

William Ruckelshaus, who has made the plunge twice, found a renewed sense of self-worth when he left the Environmental Protection Agency in 1985 and realized that he could fly to distant cities and keep appointments without aides traveling at his side - in his words, "handling all the things that so annoy the ordinary citizen." His staff was even more surprised.

"I made a trip with stops in several cities, and as I got to each one, I'd call my old staff at EPA and I'd just say, `I made it,' " said Ruckelshaus, now chief executive officer and chairman of the board of Browning-Ferris Industries. "Whatever your value to the world is, in the eyes of your staff, it's not in being able to answer your own phone, get on and off planes or keep your own schedule."

For those who survive the bends, there is often contentment on the outside. "One of the nicest things is you're not constantly talking about the government," said Lehman, now an investment banker in New York. Schultze, now a Brookings Institution scholar, likes the freedom to write about his ideas on economics without having to argue with people who disagree. "As a general proposition," he said, "the real world is a kinder, gentler place."

Ruckelshaus said he prefers anonymity to the intense celebrity of 1973, when he resigned as deputy attorney general rather than carry out President Nixon's order to fire Watergate special prosecutor Archibald Cox. There are drawbacks, however, to fading out of public memory, he cautioned.

"I find that as time goes by, people may recognize the name but they can't place you," he said. "They say, `Weren't you involved in Watergate some way?' They look at you like they wonder how long you've been out of jail."