WASHINGTON (AP) — Just when you thought you had the president's health care law figured out, it's changing.

Some questions and answers about what's afoot and who's affected:

Q: What's the nub of the change, and why is President Barack Obama changing course at this late date?

A: The president is letting insurance companies offer people another year of coverage under their existing plans even if those plans don't meet the requirements set out in his health care overhaul law. He's doing so because of mounting frustration — even anger — over the millions of cancellation notices that have been going out to Americans whose plans don't measure up to the law's coverage standards.

Q: Problem solved?

A: Not so fast. Obama's so-called fix doesn't force insurance companies to do anything. It just gives them the option of extending old plans for existing customers in the individual market, and only if state insurance commissioners also give their OK.

Q: Sounds like a no-brainer. Why wouldn't insurance companies let people re-up?

A: The companies aren't happy about being thrown a curve ball after they've already firmed up 2014 rates and plans. It will take a while to see how many of them agree to reinstate old plans for another year — and at what price.

Q: What's the early word?

A: Most companies and state insurance commissioners say they need time to study the changes before making a commitment. Aetna Inc., the nation's third largest health insurer, said it plans to extend some of its canceled policies. Washington state's insurance commissioner said he won't allow insurance companies there to extend the old policies. He said people can get better coverage on the new health care exchange.

Q: Why not force insurance companies to extend those old policies, not just give them that option?

A: That's a more radical step. Some Democrats want that to happen but it almost certainly would require legislation from Congress — not just a presidential decision — and Republicans would object to such a stiff new requirement on the insurance industry. More steps may be required, though, to restore coverage for people losing it.

Q: The changes mainly affect the 5 percent of people who get their own insurance policies through the individual market. What's the big deal?

A: In a country of more than 300 million people, 5 percent is a big number. Roughly 14 million people buy their own policies, and many of those plans are not just junk insurance, contrary to what White House officials suggest. Already, more than 4 million people have gotten cancellation notices. And some small businesses are losing coverage for their workers too.

Plus, if the government can't get its HealthCare.gov website running better by Dec. 15, some people who got cancellations run the risk of having a break in coverage. The health care law was supposed to reduce the number of uninsured people, not increase it.

Q: So people who successfully make the switch to the new insurance marketplaces can rest easy?

A: Not really. If lots of healthy people who get cheaper insurance through the individual market end up keeping that coverage instead of switching to the more robust plans offered through "Obamacare," that could weaken the financial footing of plans offered by the insurance marketplaces.

Q: How so?

A: People with current plans are a known risk to insurers. At some point, they all had to pass the stiff medical screening that the law forbids starting next year. Insurers were counting on premiums from those with current individual plans to help balance out the cost of care for people who have been shut out of the system, and who represent a potentially high risk. To the extent that healthier people stay out of the new insurance pool being created under the law, that would raise costs.

Q: What would happen then?

A: You guessed it: higher rates, potentially. Premiums for 2014 are set; where the increases would show up is in premiums for 2015. In a letter to state insurance commissioners Thursday, the Obama administration referred to the risk of "unanticipated changes in premium revenue." It promised to provide assistance through other provisions of the health care law.

Q: I get my insurance through my job. Sounds like I don't need to worry.

A: The vast majority of people with employer-based plans shouldn't be affected by the changes announced by Obama.

Q: The health care law was signed into law in 2010. Why is this issue coming up at the last minute?

A: The Obama administration miscalculated — big time — how many people would lose coverage in the transition to the new health insurance marketplace. It specified that people who had plans before the law took effect could hang on to those plans. But it didn't anticipate the big wave of cancellations among people who had plans that changed after the law took effect or who bought new plans after the law kicked in.

Q: The president says "this fix" won't solve every problem and that doing more will require working with Congress. What else needs to be done? And is there any hope of Obama and the Congress agreeing on changes?

A: Before Washington became so politically polarized, major legislation was usually followed within a year or two by a "technical corrections" bill that addressed inevitable unintended consequences and shortcomings. A bill as massive as the Affordable Care Act has many such issues, which the administration has tried to address through regulations, "guidance" and other administrative steps. For example, the White House last summer delayed the law's employer coverage requirement by one year to allow more time to work out regulatory issues.

Obama seems to be yearning for a return to earlier days, but Republicans are so adamant in opposing the health care law that it seems far from likely.