Here's a realistic video showing raising a reed a semitone and lowering another reed a semitone.
With good technique, you will not change the shape of the reed. This is important because we don't want to undo our work. You can't do reed work and change the shape of a reed without affecting the tuning. So after reed work, you must let the reed settle and then correct the tuning. If you bent the reed out of shape when you tuned it, you'd be stuck in a never ending loop of working against yourself.