What is the test for replacing a juror with an alternate juror?

Shortly after the start of deliberations, it became necessary to replace a juror with an alternate juror, and both parties so stipulated. In People v. Collins (1976) 17 Cal.3d 687, 694, 131 Cal.Rptr. 782, 552 P.2d 742, we interpreted Penal Code section 1089 to require that, in such situations "the court instruct the jury to set aside and disregard all past deliberations [45 Cal.3d 405] and begin deliberating anew. The jury should be further advised that one of its members has been discharged and replaced with an alternate juror as provided by law; that the law grants to the People and to the defendant the right to a verdict reached only after full participation of the 12 jurors who ultimately return a verdict; that this right may only be assured if the jury begins deliberations again from the beginning; and that each remaining original juror must set aside and disregard the earlier deliberations as if they had not been had."