If an expert report changes the expert’s opinion, what must occur for the reports to be used?

The requirement that all parties must be served with the new report if an expert's opinion has changed is essential for ensuring fairness and transparency in legal proceedings. This process allows all parties involved in the case to review, consider, and respond to the updated information provided by the expert, which can significantly affect the case's outcome.

Serving all parties with the new report aligns with the principles of natural justice and procedural fairness, ensuring that no party is blindsided by changes that could influence the trial or arbitration process. It upholds the adversarial system by allowing both sides the opportunity to prepare for discussions or challenges regarding the revised opinion presented by the expert.

The other options do not adequately safeguard the interests of all parties involved. For instance, requiring the expert to personally present the changes could be impractical and may unduly burden the court system. Using the report without any further action would disregard the rights of other parties to be informed of significant changes, and simply reporting changes to the court without involving all parties might not provide them the chance to respond adequately. Thus, serving all parties with the new report is the correct approach to maintaining procedural integrity.