(2) If, after the jury has begun deliberations, any juror dies or is unable to perform the duty because of illness or other sufficient cause, the court shall discharge the juror from the case and may draw the name of an alternate juror to replace the discharged juror if:
(a) An alternate juror is available and has not yet been discharged; and
(b) Both parties agreed to the substitution after the jury was selected but prior to the beginning of the trial.
(3) If an alternate juror replaces a juror under this section after deliberations have begun, the court shall instruct the jury to begin deliberations anew.
(4) The court may retain alternate jurors after the case is submitted to the jury to replace jurors as provided in subsection (2) of this section. An alternate juror retained under this subsection shall not attend or otherwise participate in deliberations unless the alternate juror is selected to replace a juror.
(5) An alternate juror who does not replace a juror as provided in subsection (1) or (2) of this section and who is not retained as provided in subsection (4) of this section shall be discharged after deliberations have begun. [Amended by 1991 c.725 §3; 2005 c.463 §§18,19; 2007 c.16 §8; 2017 c.359 §2]