The Obama administration has quietly reworked rules and computer code for to try to stem an outpouring of discontent by some Americans who have discovered that the health plans they bought do not include their old doctors or allow them to add new babies or spouses.

Under changes that have not been disclosed to the public, the government will temporarily allow consumers who have gotten coverage through the new online insurance marketplace to switch health plans to a limited degree.

In a memo distributed Thursday night to insurers, federal health officials said that people may pick a different health plan before the end of March if they are dissatisfied with the one they chose, but only if they stay with the same insurer and generally the same level of coverage. The 14-page memo, obtained by The Washington Post, also says people will be given more freedom and a longer opportunity to get a new health plan if they can prove that, the Web site for the new marketplace, displayed inaccurate information about the benefits that a health plan offers.

In addition, now has a “Report a Life Change” button, the memo says, enabling people to tinker with their plans if they have added members to their family, moved, gotten out of prison, or undergone other changes that affect the insurance they want. Even as the improvement was being announced to insurers, this aspect of the computer system still is not working reliably, according to an individual familiar with the situation who spoke on the condition of anonymity to talk about internal government work.

For the first time, people will be able to end their coverage with two weeks' notice. And a computer flaw has been fixed in order to stop a problem known as “looping” in which some people have been shuttled back and forth between the marketplace and their state Medicaid program, unable to get insurance from either one.

Taken together, the changes are the first major response by the Centers for Medicare and Medicaid Services (CMS), the agency overseeing, since the start of January, when coverage began to take effect. The changes reflect recent work — still underway — to improve the computer system for the marketplace, as well as fresh thinking about the needs of people who are buying the coverage, some for the first time.

The inability to adjust coverage in tandem with changing life circumstances was becoming a major frustration for consumers and the enrollment specialists around the country who help people sign up through the marketplace. Federal officials and government contractors working on had made “change in circumstance” a top priority lately. According to knowledgeable individuals inside and outside the government, tests have been underway this week to find out whether new software intended to fix this shortcoming actually worked.

Similarly, the computer system was not, until now, designed in a way that let people cancel insurance. In one instance, a couple enrolled for coverage in December, but the husband died before the health plan took effect Jan. 1, according to an official familiar with the case, who said the widow has been unable to cancel her late husband’s part of the policy.

In other instances, federal officials have rethought some of the marketplace’s rules, as it has become clear that some of the customers who have used purchased a health plan without fully understanding its benefits — or which doctors and other health-care practitioners were part of its network.

Specifically, the new policy says consumers may make changes before March 31, the end of an open enrollment period that began in October, if they want to “move to a plan with a more inclusive provider network” or fit within “other isolated circumstances” according to the memo, which does not define what the other circumstances might be. People who switch must stay with the same insurer and tier of coverage.

Asked about the new rule, a CMS spokesman, Aaron Albright, said: “We added this new flexibility, recognizing that many consumers are using a new system and getting coverage for the first time.” CMS officials had not decided when they were going to announce the change to the public.

According to the most recent federal figures, about 3 million Americans had signed up for health plans as of late January through the federal marketplace operating in three dozen states and separate marketplaces in 14 states. It is unclear how many of those people have paid their first insurance premium — the step needed to become insured.

Karen Pollitz, a senior fellow at the Kaiser Family Foundation who specializes in consumer assistance issues, said that most private insurance allows people to switch to any other health plans during open enrollment periods, not just to other plans offered by the same insurer.

Under another element of the rules spelled out in the memo, consumers might be able, during open enrollment periods this year and in the future, to switch insurers through a different means: refusing to pay their insurance premium so that the insurer cancels their policy. In that circumstance, the memo says, people can start over to apply for a plan.

Robert Zirkelbach, a spokesman for America’s Health Insurance Plans, the industry’s main trade group, said, “Health plans want to make sure consumers are in health plans that meet their needs and they’re happy with.”