Washington (CNN) A frenzied 24 hours filled with hushed deliberations on Capitol Hill, senior-level meetings at the White House and back-to-back phone calls with the President came to an end Wednesday -- quietly and unceremoniously.

Well before midnight, this much was clear: Republicans still had no deal on their health care bill to repeal Obamacare, as a Thursday vote loomed around the corner.

House Speaker Paul Ryan and his top deputies huddled with a group of moderate Republicans in the Speaker's office Wednesday night, as members of the conservative House Freedom Caucus sounded increasingly optimistic that they were close to getting a major concession from the White House.

Hours later, Ryan and his top deputies never came out to speak to the cameras and dozens of reporters waiting outside, and it was clear that leadership had no good news to share. With the exception of a few members who rushed away without speaking to press, all leaders in the room, including Ryan, appeared to have ducked out using side exits.

While this gathering was wrapping up, House leaders had gotten more bad news: GOP Rep. Charlie Dent, the leader of the moderate Tuesday Group, released a statement opposing the current bill spearheaded by Ryan and President Trump.

The late-night session in Ryan's office came soon after what appeared to be a major breakthrough in the impasse. The Freedom Caucus, which had stubbornly opposed the GOP bill for days, was suddenly optimistic that a deal was possible. The White House was offering a provision that would strip the so-called "essential health benefits" from the House bill, and GOP leadership indicated they were open to this change.

Late Wednesday, Freedom Caucus Chairman Mark Meadows said: "We are very hopeful we can get this done."

Now, Trump and his GOP colleagues on Capitol Hill head into Thursday still unclear of the fate of their mission to repeal Obamacare.

"It has always been the case - pull the bill one way, risk losing members on the other end," a lawmaker involved told CNN.

The vote count has been tight. According to CNN's ongoing whip count, as of Wednesday night, 24 House Republicans have flat-out said they will vote against the bill, while four more have indicated they are likely to oppose it.

With so much on the line, Trump, White House officials and Republican leaders have been lobbying their colleagues all week. On Wednesday, Trump even personally called individual members of the Freedom Caucus just as a possible deal was emerging.

Trump is not involved in the details -- "Either doesn't know, doesn't care or both," an aide told CNN -- but he is very involved in the sale now, and "appears energized by that."

Getting conservatives to back the bill will be essential because moderates are jumping ship. Even before Dent's announcement, a handful of relatively moderate Republicans hailing from New York, Iowa and New Jersey said Wednesday they would not support the bill. One lawmaker even stated bluntly that the GOP plan simply was not better than Obamacare.

GOP Rep. Frank LoBiondo of New Jersey said he was concerned about the bill's impact on his state's residents and that the proposal "is not as good as or better than what we currently have."

The prospects of cutting out the requirement that insurance plans cover essential health benefits would further lead to moderates turning away from the GOP proposal. Trump and Ryan must get 216 Republicans on board and can afford only 21 defections, if no Democrat joins them.

"There's a certain amount of gamesmanship going on here -- a little bit of chicken," GOP Rep. Tom Cole told CNN on Wednesday.

As deliberations continue, 2018 is on every Republican's mind.

Trump warned of big losses at the ballot box if Republicans fail to repeal and replace Obamacare, and the White House insists there is no alternative legislation or plan if they fail. "There is no Plan B. There's Plan A and Plan A," said White House press secretary Sean Spicer. "We're going to get this done."

Various lawmakers who are planning to vote "no" have described to CNN having 30-to-45 minute phone calls with Trump officials in recent days. And Vice President Mike Pence and Health and Human Services Secretary Tom Price are also involved in behind-the-scenes lobbying.

Ryan's whip operation has also been in full blitz mode. The House speaker has been texting directly with some members. Majority Whip Steve Scalise and Deputy Whip Patrick McHenry have also been singling out individual Freedom Caucus members to try to peel them away from the group.

Major changes to 'essential health benefits'

Some of Trump's personal lobbying has gotten results.

According to Republican Rep. Richard Hudson, who supports the bill, Trump agreed on Wednesday to GOP Rep. Steve King's request to lobby to change the essential health benefits provision at a later point. At a meeting at the White House, Trump told King he would publicly push for the change in the Senate and King agreed to vote for the bill.

"They shook hands," Hudson told reporters. "We are voting tomorrow, no matter what, but I feel like we'll have the votes."

Separately, GOP Rep. Lou Barletta announced Wednesday that he had switched his "no" vote to "yes" after receiving support for his legislation to deny health care credits to illegal immigrants.

Meanwhile, the White House has been busy courting the Freedom Caucus for days. According to a source, the caucus' members have been invited to visit in small groups in recent days. That effort continued Wednesday, with the group's members again paying a visit to 1600 Pennsylvania Ave.

What's in the bill

The bill introduced earlier this month would roll back many of the Obamacare taxes and eradicate the individual mandate. Instead of the subsidies available in the Affordable Care Act, the GOP plan provides Americans with refundable tax credits to purchase health insurance.

The bill also significantly restructures Medicaid and allows states to require able bodied adults to work if they want to be eligible for the program. After 2020, states will no longer be able to expand Medicaid like they could under Obamacare and states that haven't expanded the program at all are barred from doing so.

The GOP bill, however, still includes some of the most popular pieces of Obamacare, including protections for people with pre-existing conditions (though insurers would be allowed to charge higher premiums to individuals whose coverage has lapsed) and letting children stay on their parents' insurance plans until the age of 26.

The non-partisan Congressional Budget Office estimated that 24 million fewer Americans would be covered under this bill than under Obamacare by 2026 if the bill is enacted in its current form.