It almost never happens in Washington. But this was a party without a receiving line. And with good reason.

Thomas Enders, whom President Reagan unexpectedly removed only days ago as assistant secretary of state for inter-American affairs, stood in one corner. He was saying a lot of goodbyes.

His replacement, Langhorne (Tony) Motley, currently ambassador to Brazil, stood on the other side of the cavernous Benjamin Franklin Room at the State Department. Glass of wine in hand, he was being lectured by business executives on what to do in Central America.

The two never did meet in the middle.

But Enders later said, "Don't be silly. We're good friends. We were in my office for about an hour and we came down together."

Last night, Enders, a career Foreign Service officer who has been named U.S. ambassador to Spain, handled the crowd unabashedly, staying till the final minutes of the two-hour party for the Council of the Americas, an umbrella group for corporations with business interests in Latin America.

"It's a relief," he told every other person who offered condolences.

"All I'll say about this is that when you volunteer yourself into a job, you can't complain when they volunteer you out of it."

"We're sorry you're leaving," said Dominican Republic Ambassador Carlos Despradel, one of the hundreds assembled for the party.

"Yeah, I'm sorry, too," said Enders. "Twenty-eight months is a long time."

"You know, I'm with you on all of this," whispered one man.

"Well, I'm not going to say anything about it," said Enders.

Enders has been keeping a relatively low profile, dodging reporters since he was ousted from what had become a crucial State Department post. He was replaced, it was reported, because the administration appears to be moving toward a tougher position against leftist infiltration in Central America.

Meanwhile, way back in the antique-bedecked room, Motley was greeted and congratulated by some of the nation's top corporate executives. "If you can do 5 percent of what you did in Brazil for Argentina, we'll be in great shape," one said.

"We're going to try," said Motley.

Motley, who was raised in Brazil, was effusive about his predecessor.

"I've known Tom Enders for a long time, and not only is he one of the brightest men I have ever met in the intellectual sense, but he's an extraordinarily creative man," said Motley. "He's done a hell of a job."

So what is Motley going to do differently in Central America? Does the United States need to get tougher?

"I'm not going to comment on that," he said. Naturally. He will be facing confirmation hearings.

The Council on the Americas, headed by David Rockefeller, has not been ignored. In town for a two-day conference (its 14th) on Latin America affairs and problems, the group has met with everyone from Reagan on down. Last night, Undersecretary of State Lawrence Eagleburger addressed the group on behalf of Secretary of State George Shultz, giving an overview of U.S. Latin American policies.

And Shultz, detained at the White House, even whizzed in for a few words on the economy. Everyone stopped inhaling the roast beef and tempura long enough to listen. The four bars even shut down for three minutes.

Most of the business executives had few complaints about U.S. policy in Central America. Not even Rockefeller. "I don't think our job is to tell other countries how to run their affairs," said Rockefeller, edging out the door. "We have to deal with the government in power, but indicate our preference for a democratic government."

At the party's end, Rockefeller wished Enders well. After all, they did host the party together.