You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I support you now?

USER: Due to my ill health, I would like to change my existing reservation. Can you help me?

ASSISTANT: Sure, I will help you with that. May I know your name please?

USER: Please check with the name Brandon Wilson.

ASSISTANT: Sorry Brandon, there is no reservation found on your name.

USER: Oh, I guess there is a mistake happened while booking. Anyways, thank you for the information.

ASSISTANT: Thank you for approaching us, have a nice day.