I agree that you'll want to think about this carefully before doing it, but it ended up working for me... I weighed the pros and cons for a long time and then ultimately decided to reach out. I had submitted my application 6 weeks earlier and waited until Friday at 4:45PM before emailing. I had already received an invite from program A at a particular site but not from program B at the same hospital. My program A interview was scheduled for one week from the day I emailed inquiring about program B and the travel involves a cross country (LA-Boston) flight and taking several days off of work. I was very worried about coming across as presumptuous but then again felt like if they decide not to interview me because of this email, well then I was ok with not being considered for that program (also realizing I applied to way too many sites, haha). I got an email back a few hours later indicating that it would be "ideal" if I could come interview with program B on the same day that I was already scheduled to come for program A.
