What are two ways a US Supreme Court case can be changed?

That depends on what is meant by changing a Supreme Court case. The specific decision of the court cannot be changed the way an appellate court can change a trial court decision or the Supreme Court can change an appellate court or trial court decision thtough the appeal process. If changing a court case means changing the principle or precedent the case makes, I would say there really are three ways, although, none of these ways truly "changes the case". They change the law on which the case is decided so that the case is no longer of any precedential value. First, if the case results in a specific interpretation of the Constitution or an Amendment, an Amendment may be adopted to change the Constitution or Amendment that had been interpereted in order to eliminate the basis for the decision. An example is the decision in Scott v. Sanford, the Dredd Scott case. An underlying premise in that case was that slavery was not unconstitutional. Later, the Thirteenth Amendment was passed to make slavery unconstitutional, thereby "changing" the principle that slavery is constitutional. A second way is similar to the first, but involves statutes instead of the Constitution or its Amendments. If a Supreme Court case construes the wording of a statute in such a way that a specific result is obtained in a case, Congress can simply amend that statute or repeal it so the statutory basis for the decision no longer exists. Third, the decision might be overruled by a later Supreme Court case. An example is Plessy v. Ferguson, in which the Supreme Court held that separate but equal public facilities for blacks and whites was constitutionally permissible. Over a half-century later, the case of Brown v. Board of Education of Topeka ruled that separate facilities was unconstitutional. Note that none of the cases were "changed." They remain intact, but the basis for their rulings changed in the first two instances. In the third, the Supreme Court essentially decided that the principle laid down in the earlier case was appropriate when looking at the issue in modern society.