Some schools are pretty open to their applicants and encourage dialogue; however, when it comes down to choosing amongst applicants as far as who gets admitted, they're pretty mum. You may be able to schedule an appointment with the dean or associate dean of admissions, but I wouldn't choose to do so until either before or after the interview process. Dropping in the dean's office during the interview day appears in my mind a bit forward. To me it would appear that you're trying to buck the system and go above the heads of the committee. But hey, if you get in then it doesn't really matter. Meeting with the Dean or asst. Dean of admissions is actually a good thing. It shows that you're interested in the school and the program. The ideal time would be before the interview (maybe a week or so), but after the interview would be much better. Meeting with the dean after the interview looks favorable and displays your desire for that particular school.