If you have named various parties in a lawsuit as defendants and some have answered and some have not, you can dismiss without prejudice (meaning you can name that person in a new lawsuit if desired) the minor who is fifteen (15) years old.To do so, there is a form (usually a judicial council pre-approved form) that you fill out, date, sign and serbe upon all other parties in the action and file it with the court clerk where you have a copy of the document file endorsed.If you default the adult tenants, you then need to do a prove up hearing with the court for whatever relief you requested in the complaint. If the prove up is granted, you then get a judgment (judgment of eviction if an unlawful detainer action) with a court order that the tenants are to be out of your rental by a certain date.Good luck.