Legal Question in Landlord & Tenant Law in California

Once you vacate the property, an unlawful detainer action is no longer proper and should be dismissed or converted into a regular civil case because possession of the property is no longer in dispute. Ask the attorney for a dismissal or for a written stipulation to convert the case out of UD to general civil. If that doesn't work, then I would file a UD answer to prevent an eviction judgment on my record.

After filing an answer, you might follow up with a written motion to convert the case.

You need to file an answer. The unpaid rent portion of the case survives you moving out. That is why you need to answer and then have it converted to a regular case unless you are prepared to just pay everything they demand, in which case they would dismiss the whole case.