Joseph………..
Jurisdictions have different rules. Here in CT Courts, and the Federal Courts as well, the judge is on the bench when the prospective jury panel is brought in. He introduces the case, him/herself, the attorneys, names of plaintiff, defendant, major witnesses and asks if any are known to the prospective jurors. If any raises a hand to say yes, the judge questions the juror candidate to determine whether it is a problem. The judge then lays out the timing of the trial: when it will begin, approximately how many days it will take, whether it might require sequestration. Again if any juror candidate raises a hand stating a conflict, the judges questions and makes a determination. Only then do the attorneys start the voir dire process. The judge often asks questions as well.
Last year, I was called for jury duty. When my group was called before the judge, I did not know the Judge (it was her first case in this district) or attorneys (all were from out of state representing the two corporations in a civil suit). However the judge announced that the trial would start on Tuesday and take three days. I raised my hand to indicate a conflict. The judge asked why and I explained that I was representing a client in a case starting Wednesday in US District Court starting Wednesday. I was immediately excused. It is far easier to get another juror than reschedule a Federal case.