How do I change the RCIC on a case?

From the case, open the Ownership panel and select a new owning RCIC. The transfer is logged in the audit trail with the reason you enter.

For bulk transfers, use Cases → Bulk Actions → Reassign, which lets you move up to 100 cases at once between owners.

The client is not automatically notified of the change. Whether and how to notify the client is your firm's call; a suggested notification template is available under Settings → Templates.