Ann Levine has collected some good information on transferring law schools after 1L year.
Transferring is a real option for some students. However, it’s more difficult than most imagine. To transfer successfully (to a higher tier) you really have to be one of the top students in your class. Many students tend to think that they will be in this rare company in their class, but of course the odds are against you.
Law school is not like college where you might be able to take a few courses at community college before transferring to State U. It’s difficult to do, not only because most students do not have the credentials but, as some of Ann’s links point out, law schools try hard to get you to stay. It’s far better to go to the best school you can at the outset than to hope to transfer later.