A last-minute change in the court docket, has moved the opening day of the trial before the Superior Court of the rioters sentenced several weeks ago by Judge Michael S. Sullivan of the Charles-town District Court, from this morning to Friday morning. This latest change in date brings the trial very near to the close of the court session which ends Monday. Friday morning will be occupied with the selection of the jury and it is expected that the approach of the end of, the session will hasten the conduct of the trial. No reason for the change in the date of the trial was announced.