(Adds Pence in paragraph 11)
By Susan Cornwell and David Morgan
WASHINGTON, March 17 (Reuters) - U.S. President Donald Trump on Friday agreed to changes in the Republican plan for Obamacare, conservative lawmakers said, as he stepped up his fight to win support for the bill ahead of a vote in the House of Representatives next week.
Republicans remain deeply divided over their U.S. healthcare overhaul, which is Trump's first major legislative initiative and aims to fulfill his campaign pledge to repeal and replace the healthcare program of his Democratic predecessor, Barack Obama.
House Republicans are fast-tracking the legislation and it is expected see its fourth and final House committee hearing on Wednesday. It could go to a vote by the Republican-dominated House on Thursday, setting up another battle in the Senate, which also has a Republican majority.
House Republicans leaving a White House meeting with Trump, as well as a Capitol Hill meeting with House Speaker Paul Ryan and Health and Human Services Secretary Tom Price, listed several changes they expect to be made in order to attract both moderate and conservative party members who are currently waffling about their support.
House Budget Committee Chairman Diane Black, who attended the Capitol Hill session, said there very likely would be changes to tax credits offered in the bill to do more for older, lower-income people - something Republican moderates have sought.
Conservative Republicans who met Trump said he agreed to changes on the Medicaid government insurance program for the poor. These include work requirements for able-bodied, childless Medicaid recipients, said Representative Mark Walker, chairman of the Republican Study Committee, the largest House conservative group. Walker said he now supported the bill.
Expected changes also would provide states with the option to receive a federal lump sum block grant for Medicaid and latitude to manage the program as they see fit, Walker said in a statement.
In a letter on Thursday to Ryan and Senate Republican leader Mitch McConnell, the Republican governors of Ohio, Michigan, Nevada and Arkansas said the current bill does not provide new flexibility for states but shifts significant costs to them.
Trump met with about a dozen House conservatives at the White House and afterward declared that he had won them over to the plan, known formally as the American Health Care Act.
"I'm 100 percent behind this," Trump told reporters after the meeting. "We made certain changes but frankly very little."
Vice President Mike Pence was due in Florida on Saturday to sell the bill to small businesses, the White House said.
NOT ALL CONVINCED
But there was no sign of changes to address a top priority of the hard-line conservative House Freedom Caucus, which wants to bring health insurance premiums down quickly. The Freedom Caucus did not attend the White House meeting.
Representative Mark Meadows, the chairman of the group, expressed frustration that House leaders were talking about making the Medicaid work requirement optional - which he said "doesn't move the ball more than a couple yards on a very long playing field."
Representative Justin Amash, another member of the Freedom Caucus, tweeted: "Absolutely not true that conservatives have flipped to yes on the health care bill. It doesn't repeal Obamacare. It remains a disaster."
Meadows said his group will propose an amendment on Monday.
Representative Charlie Dent, a Republican moderate, said the House bill should be crafted to win support in the Senate, where numerous Republicans have voiced skepticism.
"I don't like the idea of just sending a bill over which they can gut and send back," Dent said.
Ryan, the chief proponent of the plan, acknowledged the challenges of winning over lawmakers.
"There are people from the middle and from the right who have various concerns," he said at a conservative forum. "We're trying to make sure that we address as many of these concerns as possible without destroying the bill ... and without losing votes but adding votes."
Democrats have roundly rejected the Republicans proposal, saying it harms the poor, elderly and working families while offering tax cuts to rich Americans and companies.
In his meeting with House Republicans Friday, Price talked to lawmakers about other changes the department could make through the rules and official guidance it uses to implement the healthcare law. These include possibly altering the health benefits that the law requires insurance plans to cover.
The nonpartisan Congressional Budget Office said on Monday that 14 million Americans would lose medical insurance next year under the Republican plan. Obamacare expanded insurance to about 20 million Americans.
(Reporting by Susan Cornwell and David Morgan; Additional reporting by Susan Heavey and David Alexander; Editing by Bill Trott and Chizu Nomiyama)