1. A grand jury shall serve until discharged by the court and may be so discharged at any time after the expiration of 1 year. At any time for cause shown the court may excuse a juror either temporarily or permanently, and in the latter event the court may impanel an alternate grand juror in place of the juror excused.
2. Where the court is composed of more than one judge, any judge may discharge or excuse a juror; but if any other judge notifies the judge so acting, in writing within 24 hours after the action is taken, that the judge objects, the action stands rescinded and is not effective unless the concurrence of a majority of the judges composing the court is obtained.