John B. Anderson has changed his mind about Sen. Edward M. Kennedy. Now he ways he is not about to withdraw from the presidential race if Kennedy wins the Democratic nomination.

Actually, says the independent presidential hopeful, he never thought Kennedy had a chance of winning anyway, and all the nice things he had to say about Kennedy after they met last week were misinterpreted.

"No secret deals were made," the Illinois congressman told a news conference here, insisting he never intended to withdraw. "There wasn't any alliance -- or pact -- struck."

Anderson has been plagued by questions all week about his highly publicized meeting with Kennedy. When it occurred. Democrats thought it was a stroke of genius, but day by day it has become an increasing liability.

All he was really trying to do, Anderson said today, was to "reach out" to Democrats for support. "What better place is there to go for support than to a prominent member of the Democratic Party?"

However, after last week's meeting, when asked if he would withdraw if someone other than Carter were nominated, Anderson said: "It would only be prudent for one like myself who believes very much in the two-party system to perhaps reconsider what my position would be."

Later he added, "I'm not running because I'm attacking the two-party system nominating process that apparently is destined to give us nominees like President Carter and Ronald Reagan."

The highly publicized meeting was seen as giving Kennedy's long-shot bid for the nomination a much-needed boost. If Anderson were out of the race, Kennedy supporters argued, their man would stand a far better chance than Carter of beating Ronald Reagan in the fall.

Anderson's part in the affair received mixed reviews, however. Some, like Democratic National Chairman John White, thought it a stroke of political genius.

'It was a great gimmick," White said in an interview. "It got him on alll three networks at a time when his campaign was dead in the water."

But when Anderson awoke in Michigan yesterday, he was greeted by a blistering Detroit News editorial accusing him of being a Supremely mutable hustler."

"It exposes the myth that John Anderson really is the holiest candidate of them all," the editorial said. "he apparently sees nothing incongruous about toadying to a man whose superstate philosophy he opposed in Congress for lo these many years. Philosophy, obviously, rates a lower priority than access to the network television audience."

Anderson has been trying to defuse the issue all week, moving away from Kennedy inch by inch. He has brought a transcript of his remarks after the Kennedy session to each news conference and read selected excerpts, And he had told supporters, "We're not pulling out, we're pulling ahead."

Today, however, was the first time he said unequivocally that he would not withdraw if Kennedy wins the nomination.

Anderson has spent the last two days meeting with top executives of the auto and steel industries here and in Detroit in an attempt to give his candidacy credibility. Yesterday he also met with Douglas Fraser, president of the United Auto Workers union and outspoken Kennedy supporter.

Fraser and industry spokesmen -- inclulding the chief executive officers of General Motors, Ford, United States Steel and Bethlehem Steel -- all express admiration for Anderson's curiosity and grasp of issues affecting them. But he didnT get any pledges of support.

"He told me we were aboard a sinking ship and he was throwing us a lifeline," Fraser siad. "I told him that was what Ronald Reagan was telling us, too, except Reagan wants to throw us an anchor."

"I was too polite to tell him, but I know of no support for Anderson in our union," Fraser added.

Today Anderson also released the first plank -- actually a position paper -- of what will become a platform he will run on in the fall.

It was a long (14 pages) detailed document on mass transit. It called for a 10 percent annuall increase in ridership, expanded car pooling or light rail (trolley) systems, and creation of a Community Transportation Trust Fund -- similar to the Highway Trust Fund set up under the Eisenhower administration -- to provide long-term financial support for captial and operating costs of mass transit systems.

With no party apparatus to help or hamstring, a 40-member research staff has been working on a series of detailedposition papers on a host of issues which will be released over the next month. When put together, the position papers will form Anderson's platform.