1242Supplementary expert reports

1242 Supplementary expert reports (1) If an expert witness changes in a material way an opinion in an expert report that has been served, the expert witness must provide a supplementary expert report (a supplementary report) to the party who engaged the expert witness (the engaging party) stating the change and the reason for it. (2) The expert witness may provide the engaging party with other supplementary reports (also a supplementary report). (3) If an expert witness provides a supplementary report under this rule, the engaging party, and any other party having the same interest as the engaging party, must not use an earlier expert report (including an earlier supplementary report) on an issue to which the earlier report relates unless the engaging party has served a copy of the supplementary report on all active parties on whom the engaging party served the earlier report.