US President Barack Obama has announced a one-year reprieve for millions of Americans facing cancelled insurance coverage under his healthcare law.
A contrite Mr Obama said his administration "fumbled the rollout" of his flagship domestic achievement.
But insurers, who axed policies that do not meet the new minimum conditions, raised doubts over Mr Obama's fix.
A separate issue with the law is the glitches plaguing the federal website set up to sell the new insurance.
On Thursday, Mr Obama said improvements to the website, which was launched last month, would be "marked and noticeable" by the end of November.
'Loud and clear'
In the White House briefing room Mr Obama, who is currently beset by record low poll ratings, acknowledged the flaws with the law's rollout had put a "burden" on his fellow Democrats.
Many of his political allies fear a backlash in the November 2014 midterm elections over the botched rollout of the Affordable Care Act, known on both sides of the political divide as Obamacare.
In recent weeks insurance companies have sent letters to their customers announcing the cancellation of coverage that does not meet the new requirements of the law.
On Thursday, Mr Obama bowed to a wave of anger from consumers and members of Congress who have lambasted him for not keeping his promise that people would be able to hold on to their existing health plans.
He said that insurers could renew for 12 months the policies that have been cancelled, though the companies are not required to take that step.
Under the change, firms that extend those plans will be required to tell customers what medical care they do not cover, and inform them that better insurance options may be available.
Mr Obama also said he expected to have to "win back" credibility and the "confidence" of the American people in the wake of the health law's issues.
"I completely get how upsetting this can be for many Americans," he said. "To those Americans: I hear you loud and clear."
It is not known how many people could be affected by the fix. Nor is it clear if state officials, who would have to implement the changes, will do so.
'Just not fixable'
Two insurance groups swiftly questioned Mr Obama's solution.
America's Health Insurance Plans, the lobbying arm of the industry, said the proposed fix could "destabilise the market and result in higher premiums for consumers".
The National Association of Insurance Commissioners said in a statement that it was unclear how Mr Obama's proposal could be put into effect.
Ahead of the president's announcement, Republican House Speaker John Boehner insisted it was time to "scrap this law once and for all".
"You can't fix this government-run healthcare plan called Obamacare," he said of the legislation, which relies mostly on health insurance plans offered by private, for-profit companies. "It's just not fixable."
Meanwhile, the Obama administration is still working to fix its malfunctioning healthcare.gov website.
It was established by the law to enable consumers who do not get health cover through their employers or via government benefits to shop for coverage.
The problems have proven so severe that fewer than 27,000 people in 36 US states have successfully enrolled in healthcare policies on the federal website since it launched on 1 October.
About 79,000 managed to enrol using websites run by the other 14 states and Washington DC.