Sometimes they say that if you find someone willing to switch, you can, but I've never heard of anyone actually doing it.
I think it would be pretty difficult. If you want to try, I would find someone willing to switch and I would email them ASAP, before school assignments.
I know a girl from this year who was placed in La Rioja after wanting Valencia reaaaally bad. She's had a great experience so far, and this coming school year she'll be switching to Valencia. I would recommend trying it out. It never hurts to get out of your comfort zone, and if you want to renew for another year, you can always switch then. I would give it a chance.