How do I ask for a retrial?

If you are unhappy with the courts decision in your case, you can file a "motion for rehearing" or a "notice of appeal" within thirty days of the issuance of the final judgment.  You must be able to state legal reasons for your request for rehearing or appeal.  The motion for rehearing is decided by the same judge that made the ruling you disagree with.  An appeal is filed with the district court for your location. If you go the route of the appeal, be advised that there are very strict rules and procedures that must be followed or your appeal will fail.  I recommend you retain a lawyer that is familiar with appellate work.