President Barack Obama and HHS Sylvia Burwell took time to weigh in on plans to repeal the Affordable Care Act (ACA) in some of their first comments since Donald Trump’s surprising win in the Nov. 8 presidential election.

On Nov. 14, Obama gave his first press conference since Election Day, and was asked about what changes could be made by the Trump administration which most concern him. His answer was the ACA, saying Republicans have considered a repeal the Holy Grail, but actually going forward with it will be a challenge.

“Now, my view is that if they can come up with something better that actually works, and a year or two after they've replaced the Affordable Care Act with their own plan, that 25 million people have health insurance, and it's cheaper and better and running smoothly, I'll be the first one to say, that's great—congratulations,” Obama said. “If, on the other hand, whatever they're proposing results in millions of people losing coverage, and results in people who already have health insurance losing protections that were contained in the legislation, then we're going to have a problem.”

The president-elect has said he’s in favor of keeping some provisions of the ACA after meeting with Obama at the White House. Obama told reporters he had advised Trump to think through “how various issues play themselves out” before committing to a position.

In a separate event in Washington, D.C., Burwell admitted the week since the election has been “tough for many of us.” As for the incoming president’s promise to repeal the ACA, she hinted it may not be so easy, saying the act is “now woven into the fabric of our nation.”

“But rest assured, the Affordable Care Act is the law of the land,” Burwell said. “The American people do not want to go back—they want Republicans and Democrats to come together to make the law better.”

Speaking to those who will assist consumers in signing up for coverage during the open enrollment period, Burwell asked them to “keep us moving,” emphasize the subsidies available for coverage and offer help both in person and over the phone.

There’s some indication Trump’s election could boost enrollment. HHS said more than 100,000 people signed up for coverage through Healthcare.gov the day after Trump won.