You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Christopher Hall.

ASSISTANT: How may I assist you today?

USER: I need to cancel my existing reservation because my health condition was not good, can you help me?

ASSISTANT: Sure, please wait for a minute.

USER: Ok, take your own time.

ASSISTANT: I could not find nay reservation with your name in our database.

USER: That's ok, thank you for checking.

ASSISTANT: Thanks for choosing us.