UCAS Extra Help

So almost 3 months after applying for university, I've realised that I no longer actually want to do my course (genius, I know). Over the past few months, I've given more thought as to what I a) really like to do and b) what I'd like to pursue a career in (Publishing, just for some context). I've also found a few universities that offer really good publishing courses that I would love to go to.

Anyway, I wanted to know if there's anyway of finding out if courses/universities will consider Extra applications? Is it worth calling them now or to watch until Extra actually starts? And will I need to write a new personal statement considering my original course choice is quite different to what I want to do now?

Thanks!