Changing into L&S is described at https://ls.berkeley.edu/sites/default/files/advchangeofcollegepetition.pdf . But note that if you want to declare an L&S major with selective admission, you must meet the major’s admission requirements (e.g. 3.3 GPA in CS 61A, 61B, 70 for L&S CS).
Changing into CoE is much more difficult.