President Reagan, trying to fire up enthusiasm among his political appointees for the second term, yesterday cautioned them against complacency and declared, "That's some great and beautiful music we've been playing the last four years, but the way I see it, from here on in, it's shake, rattle and roll."

Reagan acknowledged in a speech to several thousand federal employes at Constitution Hall that some conservatives who came to Washington four years ago "had limited practical experience" and "there have been bureaucratic disagreements and tensions" in his first term.

But for the most part he celebrated the bright spots of the last four years and told his appointees: "in the second term , we can change history, forever."

"This weekend I want you to put up your feet and relax and don't think too much about the job," Reagan said. "And Monday, when you come in, sit down at that desk and breathe deep, because Monday the world starts over again -- it's the beginning of a brand new administration -- and we're going to make new history . . . ."

The president vowed to lower tax rates in his second term, as he did in his first, "continue to trim the size of government," and "go for economic growth" that will "give complete opportunity to every person in our country."

"We have made great strides in civil rights in our history," he said, "but blacks and Hispanics and all minority members won't have full and equal power until they have full economic power."

"We have taken control of the ship of state and changed direction," Reagan said. "And what are we going to do now? Well, the way I see it, it's All Ahead Full." Then, departing from his text, Reagan launched into an anecdote about a movie role he played on a submarine in which he shouted "All Ahead Full."

The fourth annual Executive Forum brought out most of the Cabinet and senior White House aides, sitting on chairs in front of the Marine Band in what White House counselor Edwin Meese III joked could easily be a game of "musical chairs." Meese said the latest word being passed around the White House basement was, "If my boss calls, get his name." White House chief of staff James A. Baker III, who is swapping jobs with Treasury Secretary Donald T. Regan, said he offered advice to Regan but was told, "Let Regan be Regan."

Baker said Regan probably will discover that his "most important duty at the White House is taking Lucky out for a walk." Lucky is the Reagans' 15-week-old sheep dog.

The president, seeing the entire Cabinet lined up, said with a smile, "I'll try not to take a nap."

Aside from Reagan, the warmest applause of the day went to one official who did not speak and who does not yet have a new job: U.N. Ambassador Jeane J. Kirkpatrick.

But this and other questions hanging over the second term seemed to be overshadowed by celebration over the successes of the Reagan "revolution."

Meese cited the "almost magical" effects of Reagan's tax cut, and said the president had "miraculously" reduced the growth in government spending. Now, he said, the goal is to "institutionalize the Reagan revolution."

"America's sun is rising!" said Vice President Bush. "America is back!"

Secretary of State George P. Shultz said Reagan has "changed our way of thinking" about foreign policy. He noted the forthcoming arms control talks with the Soviets and criticized what he described as "spasms of detente" in U.S.-Soviet relations in which the Soviets "smiled" and the U.S. "seemed to neglect" its defenses.

Shultz added, "Insofar as nuclear weapons are concerned we should aim at zero," and, if the technology proves possible, the United States "should change our way of thinking" from offensive weapons to defensive ones, which he called "a safety net" and "an insurance policy" against nuclear attack