Fill out the jury duty questionnaire your county sends you. If the person is unable to fill out the form, another person may fill it out for him, indicate that he has done so, and the reason therefor.Jurors hear either criminal or civil cases. In criminal cases, a district attorney acting on behalf of the citizens of Pennsylvania prosecutes a case. The system is asking if you are demanding a jury trial at this time. History of Jury Duty. This book is written for jurors selected to serve in the trial court of the Federal Government, the United States District Court. Under most circumstances, you may be excused from jury service if you are in the active military. Jury selection is one of the most critical elements of a Pennsylvania DUI trial. If you have been called to jury duty, you will serve under the One Day-One Trial System.