Legal Question in Real Estate Law in California

You file an unlawful detainer action, the same as if the had stopped paying rent and ignored the 3-Day Notice to Pay Rent or Quit.

Unless the tenant is moving out voluntarily, engage a firm that specializes in the eviction process. It is cleaner and far less expensive when you take into account the problems and delays of doing it wrong when you do this yourself. There are a series of steps, and a failure in any of them often means you start over. Even though I am an attorney and have rentals, I don't do this myself, but engage experts. Feel free to try it if you prefer, but I doubt you will want to do so the next time after experiencing the process.