You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I help you?

USER: David Wilson here. I would like to cancel my reservation due to health problem. Can you help me?

ASSISTANT: Sure, please wait for a moment to check your reservation details.

USER: Ok, take your time.

ASSISTANT: Sorry to say, no reservation found on your name in my database.

USER: No problem, thank you for your help.

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