you can contact UCI Admissions to see if their are any unpublicized methods; you are undoubtedly not the 1st frosh to decide they picked the wrong campus. But if these don’t exist then you’ll have to wait until you are a junior.
One avenue people have discussed is withdrawing entirely from school before finishing the 1st quarter and reapplying as a frosh, but nobody has ever said whether UC has agreed it is ok. And going against it working is their definition of a transfer student “You’re a transfer student if you enrolled in a regular session (fall, winter or spring) at a college or university after high school. (Taking a class or two during the summer term immediately following high school graduation doesn’t make you a transfer student.)” If you ask UC about this and they say it would work, you should get that assurance in writing (email or letter), not just over the phone.