For the second time in four years, an outsider promising fundamental change has ridden into Washington as the newly elected president, and for the second time in four years, fundamental changes are fading from view even before the new president takes the oath of office.

Perhaps this is now the meaning of "transition," a time in which campaign rhetoric is transformed into new slogans suitable for actual governing. That is certainly the process that has been going on in the Reagan transition, as it did just four years ago in the Carter one.

Hamilton Jordan helped write the new definition of transition four years and a few months ago, in an interview with Playboy magazine. It was the summer of '76, and Jordan was speculating on the Carter administration he was sure was soon to come. "If, after the inauguration," Jordan said then, "you find a Cy Vance as secretary of state and a Zbigniew Brzezinski as head of national security, then I would say we failed. And I'd quit But, "Jordan added, "that's not going to happen. You're going to see new faces, new ideas. The government is going to be run by people you have never heard of."

There is no equally juicy quotation from the new president-elect or his closest advisers, but a comparable message ran through Reagan rhetoric all during 1980. Reagan promised a new kind of government, run by "the best minds available," determined to "restore our values" and to change the course of domestic and foreign policies.

Specifically, Reagan on the stump in 1980 promised a speedy tax cut, a balanced budget probably by 1982, sharply increased defense spending, tougher foreign policies, and an early burial for Jimmy 'carter's two bureaucratic monuments, the departments of Education and Energy.

All of these promises have undergone some modification during the transition. The most radical proposition to which the Reagan camp now seems drawn calls for quick and deep cuts to the federal budget that will affect some of the most basic spending programs, including possibly Social Security. This one, ironically, was not a promise Reagan made during the campaign; on the contrary, his stump rhetoric indicated such popular federal programs would not have to be cut.

The other familiar Reagan promises have all been amended since Nov. 4, most of them in the last week. The tax cut should perhaps not be so speedy, the secretary of treasury-designate and the director-designate of the Office of Management and Budget have said; an effective date later in in the year, adding less to the impending deficit, might be preferable.

In Reagan's campaign rhetoric there wasn't the slightest doubt that the budget would be balanced by 1983; it would probably happen in 1982, the candidate said. But his new secretary of the treasury said last week that 1984 now seemed a more realistic target. (Carter, too, picked the fourth year of his administration as the magic moment when budgetary equilibrium would be achieved.)

Republicans all last year complained that Carter was not increasing the defense budget far enough beyond inflation. He offered 5 percent, they said that was too little. Now the defense secretary-designate says he sees no reason to set a fixed percentage for increased defense spending; don't be so rigid, he urged at his confirmation hearing. (The same official, Caspar W. Weinberger, has apparently decided not to hire the hardest-line defense specialists around Reagan for the senior jobs in the Pentagon, and he has been spending a lot of time in harmonious conversation with his predecessor, Harold Brown.)

A tough new foreign policy may still be in the offing, but Reagan aides have passed the word that their first moves on the major crisis of the day -- the hostages -- will be cautious, not confrontational. And the secretary of state-designate, Alexander M. Haig Jr., carefully avoided calling for new confrontations with the Soviets in his confirmation hearings, recommending instead that the United States "seek actively to shape events and, in the process, attempt to forge consensus among like-minded peoples."

Dismantle the departments of Education and Energy? No, said the designated secretary of education. Regan really just wants to reorganize that department. No, said Reagan's secretary of energy. I plan to reduce the role of the department, but not to abolish it.

Of course the last word is not in. Partly because transitioning has proven much more difficult than the Reagan group expected, the process is far from complete. Clearly, it won't be complete by the time the new administration takes office Jan. 20. Only when the rest of President Reagan's appointments and the first policy pronouncements are made will it be possible to judge whether the campaign rhetoric really has been buried.

But the movement from campaign flourishes to more conventional utterances is well under way and shows every sign of continuing. This rhetorical adjustment appears to reinforce an impression created by the new president's Cabinet and first sub-Cabinet appointments -- an impression of conventional instincts at work.

Of course, the new administration's ability to depart from conventional expectations and make its mark in its first weeks in office will depend on Reagan's skills as an executive and the effectiveness of those he has gathered around him. These remain mysterious factors after nine weeks of transition.

Many Republicans in Congress have expressed concern that the new administration is taking shape too slowly and too clumsily, or that the new president seems somehow detached from the job at hand. Transition officials admit that they are substantially behind the schedule they had set for themselves. The new administration will be but a shadow of its future self when it takes office.

Sometime between the Super Bowl and the first pitch of the baseball season the new team will get the chance to show its stuff. For the Carter administration the first big show was the "moral equivalent of war," the comprehensive energy program that James R. Schlesinger generated at the Department of Energy during 90 hectic days.Produced with all the purposefulness and energy that the Carter transition portended, that energy program turned out to be an apt metaphor for the Carter presidency; politically clumsy, oversold and then abandoned (though later revived in substantially modiofied form), never making quite the impression it was supposed to.

The Reagan camp, not surprisingly, is determined to make a different kind of first impression.