WASHINGTON — Republican senators left a White House lunch with President Donald Trump Wednesday promising a renewed effort to revive their sidelined health care bill but providing few details about how they plan to finally get the party’s signature campaign promise over the finish line.

The lunch had been put together as a last-ditch effort to revive talks on a GOP bill that has twice failed to gain the support of at least 50 senators needed to pass it. At the outset, the president urged the 49 GOP senators who attended to pass a bill that includes a replacement for the Affordable Care Act and to stay in Washington, forgoing their August recess, until they do.

"I'm ready to act," Trump said, noting that he has his "pen in hand" to sign the legislation. "For seven years you promised the American people that you would repeal Obamacare. People are hurting. Inaction is not an option and, frankly, I don't think we should leave town unless we have a health insurance plan, unless we can give our people great health care."

Trump's comments were a change of course for the president who earlier in the week advocated for the passage of simple repeal of the current law, something Senate Majority Leader Mitch McConnell had announced he would pursue.

On Wednesday, Trump had a different message, saying, "the people of this country need more than a repeal. They need a repeal and a replace."

Related: 17 Million Fewer Insured Under GOP Obamacare Repeal, CBO Says

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Trump's insistence has revived the discussions on the Better Care Reconciliation Act. After the lunch, McConnell slightly revised his plan to hold a straight repeal vote early next week, opening the door for the replacement bill once again.

"I think we all agree it's better to repeal and replace, but we could have a vote on either," McConnell said.

Senators left the meeting willing to give the effort another try before a vote next week even though most were unclear of what would come next.

"No question the meeting gave a boost to the effort," said Sen. Bob Corker, R-Tenn.

Trump didn't appear to change any minds, however, especially among moderate Republicans concerned about deep cuts to Medicaid. Another meeting will take place for all 52 Republicans who want to attend Wednesday night with Health and Human Services Secretary Tom Price and Centers for Medicare and Medicaid Services Seema Verna, focusing on bringing the centrists back into the fold.

Sen. Susan Collins, R-Maine, who has said she won't support the bill without dramatic changes, won't attend tonight's meeting, according to her spokeswoman.

And all eyes are on other skeptical senators. Sen. Dean Heller, R-Nev., is one of the members who have voiced deep reservations about the GOP bill. He was seated next to Trump during the lunch and the president made a pointed reference to him, telling senators and the gathered press that his constituents in Nevada will "appreciate what I know you're going to do."

"He wants to remain a senator doesn’t he?" Trump said of Heller, who faces a tough reelection fight next year. Heller laughed at the moment and told reporters after the meeting, "That’s President Trump being President Trump. I understand that."

But Heller said he's not ready to commit to the bill. "We’re just going to continue with the discussions for now and see what plays out at the end of the day," he said. "But there’s so many moving parts on this I don’t want to commit to anything at this point."

"I’m still in a position I’ve been in for weeks which is trying to improve the bill," said Sen. Rob Portman, R-Ohio. "We had good discussion," he said, adding with a note of skepticism, "we've had them before."

Portman said that he'll continue to have discussions but before he is to vote for any bill, he wants assurances that low-income people won't lose their health care and will have access to affordable coverage.

Sen. Shelley Moore Capito, R-W.Va., said she is pleased that the president came back around to a comprehensive bill.

"We promised we would repeal and replace," Capito said. "We want to do that but we want to do it the right way. So, nobody said it was going to be easy. Obviously it isn’t and we are still working hard on it."