Can a holdout juror be substituted for an alternate juror?

A much closer question is presented by the substitution of an alternate for the holdout juror. Defendant insists he was denied due process, a fair trial, and a full and fair jury determination on all the issues. Again, we are constrained by a deferential standard of review. The determination as to whether a juror is excused for good cause rests in the discretion of the trial court. (People v. Kipp (1998) 18 Cal.4th 349, 366.)

A juror may be substituted before or after the final submission of the case to the jury if upon "good cause shown to the court [the juror] is found to be unable to perform his duty . . . ." (Pen. Code, 1089.) "The determination of 'good cause' in this context is one calling for the exercise of the court's discretion; and if there is any substantial evidence supporting that decision, it will be upheld on appeal. [Citations.] A juror's inability to perform his or her functions, however, must appear in the record as a 'demonstrable reality' and bias may not be presumed." (People v. Thomas (1990) 218 Cal.App.3d 1477, 1484.)