Science is not a stagnant thing. It is constantly changing and correcting itself. Science is better seen a process of getting information than as a body of information. One of the hallmarks of science is this self correction. In science, no idea is above being challenged or immune from criticism.
Pseudoscientists often present scientists as trying to maintain the status quo. In reality, the opposite is often true. If a physicist could collect evidence that gravity was not the curving of space but something else, they would become one of the most famous physicists of our time. The reason that this is done so rarely is that in science, you have to have the evidence. Well-accepted theories have lots of evidence behind them, and in order to overturn them you would need more evidence than supports the original claim.
One field where ideas are constantly being overturned is medicine. New drugs are studied rigorously to demonstrate effectiveness and safety. After years of study, the drug can be approved by the FDA. Once the drug is approved, people continue to test it. If at any point the drug is show to be unsafe the FDA will pull it from the market. Good doctors will prescribe treatments that have been shown to work with minimal side effects. If new risks are discovered they stop prescribing the treatment. These are both really good things.
Another good example is the Piltdown Man hoax. This was a forged fossil of a early human ancestor. The fossil reflected what paleoanthropologists at the time thought our evolutionary ancestors would look like. Because of this, the scientific community of the time did not suspect a hoax. Over time more real fossils were found and Piltdown Man became an anomaly. As it became more of an exception it started to be ignored until finally it was revealed as a hoax. For more on Piltdown Man, see Talk Origins.com.
It was Carl Sagan who said "In science it often happens that scientists say, "You know that's a really good argument; my position is mistaken," and then they actually change their minds and you never hear that old view from them again. They really do it. It doesn't happen as often as it should, because scientists are human and change is sometimes painful. But it happens every day." It is sometimes hard to admit that you are wrong, but if we don't we never move forward. Science is always striving to move forward, and therefore always correcting itself.