If the tenant surrenders possession, an unlawful detainer action is converted into a normal civil action.  At that point, but not before, the tenant can file a cross-complaint.  This decision holds that the tenant does not waive or forfeit cross-claims against the landlord by not pleading them initially in response to the unlawful detainer complaint or by surrendering possession before raising them.  The compulsory cross-complaint rule does not operate in unlawful detainer actions unless the tenant successfully files a cross-complaint or after the action is converted into an ordinary civil action by the tenant’s surrender of possession.