Transfers are not common - I have seen it before - but there are large caveats to go with it. The student must be in excellent standing with both schools. Additionally, the curriculum of both schools must be complementary. Beyond that, the school to which the student will transfer typically has to hold a special meeting of the ADCOM to deliberate on the student.
It just isn't a common practice. If you want to got to a school - I would recommend being accepted to it outright.