You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I assist you?

USER: I am Brian Anderson. Due to my health problem I want to change my reservation, can you please help me to change my reservation?

ASSISTANT: Yes, I can help you.

USER: Thank you.

ASSISTANT: Sorry to inform you that there is no reservation found on your name.

USER: That's fine. Thank you for your service.

ASSISTANT: Thank you for consulting us.