Reprinted from yesterday's late editions.

The Empress of Iran spent 20 minutes in the Oval Office Monday but she didn't get into planes or oil or things like that, according to her ambassador.

"I'm the one who has to get the slap in the face," joked the affable Ardeshir Zahedi between the courses at a dinner he gave at the Iranian embassy Monday night in Farah Diba's honor.

What she did get into, observed Sen. Frank Church of Idaho, member of the Senate Foreign Relations Committee, was "winning more friends for Iran - everytime she appears anyplace."

In the upper reaches of international power politics one could hardly do better than win the kind of friends she found at, first, Rosalynn Carter's luncheon table in the Blue Room, and later at the embassy.

If she happened to be traveling without the shah, in the view of Sen. John Sparkman of Alabama, chairman of the Foreign Relations Committee, "Maybe it is characteristic of the new age of the ladies."

Characteristic or not, it had all the earmarks of a prepatory trip for another, this one "probably," said Zahedi, to be made by the shah later this year. "We're still working out the details."

Meanwhile, the 37-year-old queen managed to pick up a few accolades of her own and told of "leaving your country with a heavy love," as she stood tall and regal in the ambassador's dining room, addressing 80 black-tie dinner guests who spanned the top levels of Congress and the administration.

"I have received many honors," said Farah Diba, "and I am very grateful. What I am trying to do in my country has been given recognition by some of your institutions."

Some of her work, but more particularly some of the shah's, was given less complimentary recognition by one of their "institutions" as well, specifically the Iranian Students Association in the United States, which dogged her trail across the United States.

They never quite made it to the Massachusetts Avenue embassy Monday night, however. A deterent may but it could also have been a District have been security, predictably heavy, regulation which prohibits demonstrations within 500 feet of an embassy.

"That would have put them (demonstrators) on the Rock Creek bridge and since we could never permit a bridge to be obstructed, it would have put them beyond it," said a District policemen.

During cocktails, the empress said she was not distressed by demonstrations against her husband or his policies "as long as I know what we are doing is correct. I don't have complexes inside," she continued. "I feel that as long as you help the majority of the people you are doing what is right. You can't make everybody happy, you know."

Whatever the street sentiment was, drawing-room sentiment was unmistakably favorable.

"Iran is one of the most important allies the United States has," said Sen. Abraham Ribicoff of Connecticut. "When you realize that 50 per cent of the world's oil comes through the Straits of Hormuz and the only armed forces to protect it are Iran's, to refuse him (arms) would be sheer stupidity on the part of the United States.

Zahedi planned the evening right down to the placement of chairs at the after-dinner musicale. There was "Pearls of the Caspian" (caviar to the uninitiated - about nine pounds worth estimated at $120 a pound), chicken kabab, price with barbarries and cumin seeds and "crown flambe aux fruits." The latter, too, was Zahedi's brainchild, built of pastry "glued together" with carmel by Ridgewell's and lighted at the precise moment waiters carried it into the dining room.

"The queen smiled," a waiter announced later, returning the spent "crown" to the kitchen.

The queen, herself, wore no crown. Her jewels were charming, modest emerald and diamond drop earrings, complemented by a diamond wrist-watch and diamond-studded evening bag. Her gown of white peau de soie and paillettes was "Italian," she said, declining to name its creator.

There was no after-dinner dancing, also on Zahedi's order, because he has, as he put it, "water under the knee" and his travels with the empress to California, Aspen, New York, Pocantico Hills and Washington in the past 12 days hadn't helped much. Next week, he said, he will enter Mayo Clinic where he expects to undergo surgery.

And if Zahedi's familiar grin belied it, his toast nonetheless contained hints to some ears that his Washington tenure might be winding down. "Whether I will be here or not . . ." and "if I'm going to be replaced . . ." left listeners dangling.

As the queen sat between Chief Justice Warren Burger and Secretary of State Cyrus Vance, watching her old friend Zahedi, who first introduced her to the shah back in 1959 when she was an architectural student at the Sorbonne. Indiana's Sen. Birch Bayh rose to end the toasts.

"Ardeshir is indeed an Iranian who has served your country in our country well," said Bayh. "We could not love him more if he were serving our country in your country."