Last month, insurance companies sent cancellation letters to hundreds of thousands of individuals and small businesses. Policies held by these customers did not offer all the essential benefits required by the new health care law. After mounting criticism from Republicans and fellow Democrats, President Obama announced last week that these plan holders would be allowed to keep their policies for one year. But many states have refused to comply with the president’s order. They say it would disrupt their insurance exchanges by allowing young, healthy people to opt out. How changes to the Affordable Care Act will affect consumers and insurance providers.