You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I aid you?

USER: I am David Clark. Due to health problems, I need to cancel my recent reservation.Can you help me please?

ASSISTANT: Sure, please wait for a while.

USER: Ok.

ASSISTANT: Sorry to say that there is no reservation found in your given name.

USER: Thanks for your information.

ASSISTANT: Thank you for approaching us.