If you don't ask to have your scores withheld when you take the test, then your scores are automatically released to any school you designate on your primary AMCAS application. (You can designate a certain number of non-AMCAS schools at the time you take the exam for free, but if you want to send scores to non-AMCAS schools later, you have to pay a fee.) Schools know if you've withheld scores, and the general opinion seems to be that they don't like it. If you withhold your scores and then later release them, you cannot designate which schools they're relased to, except, again, for non-AMCAS schools. Released means released, and they're automatically sent to any school you designate on your primary. To release the scores, you have to fill out a special AMCAS form; you can't do it on your AMCAS application. Anyone's who's applying this year, and has not released their scores yet had better do it ASAP because of AMCAS notorious propensity to screw up anything they can screw up.