5 November News Essential Do’s and Don’ts for Expert Witnesses 07. Receiving Instructions, 06. Rules and Regulations, 11. Report Writing, 14. Changing your opinion, 08. Working with Instructing Parties, 12. Responding to questions, 15. Giving Oral Evidence The expert is now closely regulated by the rules. Provided that they conduct themselves in an honest, competent and careful professional manner they are unlikely to transgress the rules. However, experience has shown that there are pitfalls, pitfalls which may have serious consequences.