When you do your AMCAS, there is a check box for whether or not you've applied to each school before (that is, a check box for each school). So as far as the schools know you're a first-time applicant, but expect questions during your interviews such as "Did you plan to take a year off after undergrad?" or "Have you applied to medical school before?" I've had all these questions and more, and had to cough up to the fact that I'd applied before at almost all my new schools. It's not a big deal, in fact several interviewers said it just shows determination. Also, be prepared to automatically give a reason for why you didn't apply to their school the first time.