I don't know if it looks bad but I had the worst luck last year when I switched my interview date. I received an interview at Ohio St. on a specific date but I had already bought flight tickets, hotel, car, ect for another interview at Buffalo on the same day so I changed the interview at Ohio to their next available interview date. Anyway when I got to Buffalo it snowed 2 and half feet, the city shut down, and my interview was canceled at the school because they didn't have any power. I had a phone interview and needless to say I didn't get in at Buffalo. Then my interview at Ohio was on December 1st and I got stuck in the airport waiting for a blizzard to leave Chicago so I could go to Ohio. Needless to say my flight was canceled and I missed the interview at Ohio. Luckily I had already found out that day that I was accepted at Temple and I didn't have to reschedule my interview at Ohio, but I did loose like 150 bucks in hotels and car rentals. Anyway whether or not it looks bad to switch interviews I don't know, but it brought me a lot of bad luck!👍