By Deirdre Walsh, Lauren Fox and MJ Lee CNN

WASHINGTON (CNN) -- Republican leaders plan a vote Thursday to repeal and replace much of Obamacare, optimistic that President Donald Trump can help them close the deal, multiple House Republican sources tell CNN.

Leaders continue to work toward the 216 votes needed to pass the health care bill led by House Speaker Paul Ryan, and believe some of the changes they are willing to make will secure additional support.

Friday morning, members of the Republican Study Committee -- who have expressed serious doubts about the House's health care bill -- emerged from a meeting at the White House backing the legislation.

Trump said Friday he is "100% in favor" of the health care measure.

"I just want to let the world know I am 100% in favor and these folks -- and they are tough and they love their constituents and they love their country -- these folks were nos, mostly nos yesterday and now every single one is a yes," the President said.

North Carolina Rep. Mark Walker, the chairman of the RSC, told reporters he and other members were on a conference call Thursday night up until midnight discussing the two items they wanted to secure their support and had already decided they could support the bill with those revisions when they met with the President.

The President himself acknowledged the difficulty in making changes to the bill, saying during a news conference Friday, "You do something for one side and the other side doesn't like it."

Walker told reporters at the Capitol that 16 out of 17 of the RSC's steering committee members were now on board with the bill. Only one, Rep. Jim Jordan -- a member of the House Freedom Caucus -- remained opposed.

"You're looking at some of the top conservatives in the House," he said. "We stand united today to move this forward for the American people."

What's new in the bill

Republican members have been assured that the current House bill is on track and being reworked to include the option for states to impose work requirements for able-bodied adults who are on Medicaid, something the RSC has been lobbying for.

The RSC also was told that states were given the option to receive block grant funding rather than per capita funding.

Changes may also include making tax credits for older Americans more generous, an item that could win over some moderates.

In tinkering around the edges, leadership is optimistic that they can cobble together enough votes from both corners of their party to pass their legislation Thursday and move it onto the Senate where it faces another set of challenges and even more narrow math.

Thursday is also the seventh anniversary of President Barack Obama signing the Affordable Care Act into law.

During the RSC meeting at the White House, Health Secretary Tom Price reminded members that the administration is fully behind the House's bill and that he remains committed to making rule changes at administrative level to help Republicans settles some of their concerns.

Trump's lobbying is working, members say

Passing a repeal and replacement of Obamacare remains the first major legislative test for Trump, a president who never held elected office before January, but his Capitol Hill allies say can close this deal.

"The fact is he understands and he's a businessman and he understands the art of the deal and he's listening to the concerns here in the House and the Senate and he wants to try to get this thing moving forward," said Rep. Lou Barletta, a Republican from Pennsylvania and early Trump endorser.

House Republican Whip Steve Scalise said that Trump's message to the RSC was that with the changes "I am 1,000%for the bill, and I want members to vote for the bill."

The House's top vote counter still recognizes that there's work to do, however.

"There are other members who still aren't there yet, but a lot of them are working to get there," Scalise said. "The President made it clear this morning that he is all in and I think a lot of members were waiting to see if the President was going to fully sign on"

"I think they are about to realize just how popular this President is and how much the American people want to have a bill on his desk that repeals and replaces Obamacare and this is the bill that President Trump wants us on his desk," he added.

Kentucky GOP Rep. Andy Barr, who was leaning against the bill, but is now supporting it after the meeting this morning told reporters said "absolutely it helps" that the President was so personally engaged this morning.

"That's a sign of presidential leadership," Barr said.

Freedom Caucus says it's not yet on board

While the White House and GOP leaders are touting the change of heart among Republican Study Committee members, the House Freedom Caucus still remains opposed to the health care bill.

The conservative group balked at Trump's announcement that all RSC members at the White House meeting are now "yes" on the health care bill, insisting that the development does not at all change the widespread opposition within the HFC to the bill.

"The announcement that all the RSC members would be for it doesn't change our group at all," a Freedom Caucus source told CNN.

One example of why they won't be swayed: the optional work requirement provision. The source said mandatory work requirement would have been viewed as progress, but that making it optional doesn't do anything to sway their members.

On the news that a House vote is likely to be scheduled for next Thursday, the Freedom Caucus source said: "I don't know what they're thinking. They do not have the numbers."

Governors worry about Medicaid impact

The GOP replacement also is meeting resistance from some Republican governors.

Govs. John Kasich of Ohio, Rick Snyder of Michigan, Brian Sandoval of Nevada and Asa Hutchinson of Arkansas sent a letter Thursday to Ryan and Senate Majority Leader Mitch McConnell expressing concerns about the plan's potential effect on their states.

They wrote the current GOP proposal's approach to Medicaid "provides almost no new flexibility for states, does not ensure the resources necessary to make sure no one is left out, and shifts significant new costs to states."

Instead, the four governors urged the two leaders to consider their alternative healthcare plan that would allow each state "to pursue Medicaid transformation in its own way."

Through Obamacare there were 31 states that expanded Medicaid to low-income adults, including 16 run by Republican governors.

CNN's Dana Bash, Sunlen Serfaty, Terence Burlij and Jeremy Diamond contributed to this report.

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