If you cancel your score after seeing it immediately after taking the computer-delivered version of the GRE, you can reinstate the score if you want. Once you cancel the score, it disappears off your record. If within 60 days you change your mind, you can pay $50 to have the score reinstated. There really isn't much of a reason to cancel your score, though. You get to select which scores universities receive. This means you don't have to send them the scores that you don't like.