In a significant turnabout of its hard-line posture against Israel, a high official of the Palestine Liberation Organization said Friday that the organization is ready to accept conditions for Israel's future safety and to vouch for a two-state formula that would provide for both a Palestinian and an Israeli state coexisting side by side.

"The future of Israel is provided for and guaranteed under our formula," said Abdel Rahman, a confidant and spokesman for PLO chairman Yasser Arafat. "We (the PLO) are together . . . all the factions are here . . . the intifada (uprising) brought us together."Rahman, speaking officially in a private interview, said the PLO and its governing entity, the Palestine National Council, which Saturday will begin a 31/2-day meeting that will culminate with the declaration of the state of Palestine, have evolved greatly since the beginning of the uprising in the Israeli occupied territories almost a year ago.

The meeting of the 450-member council is considered a historic moment, coming in the wake of the Palestinian uprising, or intifada, which began Dec. 8 against Israel's 21-year occupation of the territories it seized from Jordan and Egypt in the 1967 Mideast War.

More than 300 Palestinians and 11 Israelis have been killed in the intifada.

Israeli officials say a declaration of independence will hurt chances for peace.

"This is our moment," Arafat said Friday. "For 40 years the Palestinian people have been waiting for their country, and now the intifada in the territories has made it possible. And what we will do here is to recognize the heroes andthe martyrs of the intifada and to follow their wishes by recognizing the statehood of the country of Palestine." The British Broadcasting Corporation transmitted the Arafat statement from Algiers.

"The American people will be surprised by what will come from this (meeting)," Rahman said. "All three United Nations resolutions (which recognize Israel and provide for a peaceful means to settle the Palestinian dilemma) are in the list."

U.N. resolutions 181, 242 and 338 are all key policy elements, which the United States and Israel demand as fundamental to any settlement of the Palestinianissue.

Rahman further indicated that the PLO and the entire PNC board, made up of 70 delegates, are ready to phrase the declaration expected to come from this meeting in such language that the United States, Israel's chief ally and protector, would find it acceptable.

The historic 19th sesion of the PNC will begin Saturday with a speech from Arafat, who arrived here Friday. He is expected to outline to the PNC its historic moment and to urge it to choose the document declaring the existence of the state of Palestine.

"The idea is to make such a conciliatory statement that neither the Americans nor even the Israelis can pass it by," a source close to the PLO said.

But the PNC has a tremendously hard road ahead in the next 31/2 days. It is made up of myriad factions, some of which do not trust the others.

"I would have to see it to believe it," a U.S. official said of the conciliatory statement made by Rahman. "It is one thing for a spokesman to say it andanother for all the PNC to give its approval. Frankly, I'd be flabergasted . . .we would have to react. It'd be difficult to pass up."