Even though the House has voted more than 60 times to repeal the Affordable Care Act and President-elect Donald Trump has pledged to repeal and replace President Barack Obama’s signature legislative triumph, a key Republican senator Thursday said it will take years to overhaul the program.

Sen. Lamar Alexander, R-Tenn., who chairs the Senate Health, Education, Labor and Pensions Committee, told reporters said the law cannot be replaced the first day Trump is in office and that change will be incremental. Additionally, overhauling the law will be complicated by the rancor that has built up in Congress. It’s like “the Hatfields and the McCoys … shooting at each other,” he said.

“I imagine this will take several years to completely make this transition,” Alexander said. “We need to gradually move those decisions back to states and to individuals and do it in a way that does no harm to people today.”

Trump said in a “60 Minutes” interview Sunday he would keep at least two provisions of the ACA: the provision guaranteeing coverage to people with pre-existing conditions and the provision allowing children to stay on their parents’ policies until they turn 26.

Republicans are expected to begin the repeal process in January, Politico reported, noting the law currently covers 20 million people.

“No one is banging on my door saying, ‘Save this program,’" Rep. John Shimkus, R-Ill., said.

Alexander said changing the insurance program will require Democratic support since Republicans do not have a filibuster-proof majority in the Senate.

"Eventually, we'll need 60 votes to complete the process of replacing Obamacare," he said.

Without offering specifics, Alexander said the GOP replacement would turn more control back to the states.

"What we need to do is make lower-cost insurance available to most Americans," he said. "The exchanges are the problem. They need to be repealed; the individual mandate needs to be repealed. ... But I think what we need to focus on first is what we would replace it with and what are the steps we would take to do that."

Sen. Orrin Hatch, R-Utah, head of the Senate Finance Committee, warned the process won’t be easy, “but I think Democrats and Republicans will work together to get a better system.”

Sen. Lindsey Graham, R-S.C., agreed, saying it’s “going to be harder than a lot of us think.”

Republicans need to decide whether to repeal the law through the budget reconciliation process, which would speed efforts along by avoiding filibuster. Theoretically they could delay the implementation until replacement proposals are up and running.

“We understand what the problems are and we know that Obamacare is a destructive force in America and almost everybody admits it,” Hatch said. “It doesn’t work, it’s costing too much money, it isn’t evolving into better health care and we have to do something to straighten it out.”

Health insurers are urging Trump and the Republicans not to disrupt the system.

“At the moment, our message is, ‘Let’s be thoughtful,’” Ceci Connolly, chief executive officer of the Alliance of Community Health Plans, told Bloomberg. “Let’s not disrupt millions of people.”