You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I serve you today?

USER: Due to some problems my trip was cancelled so can you please cancel my flight ticket?

ASSISTANT: Sure, we are here to help you.

USER: Thank you for your response.

ASSISTANT: May I know your name please?

USER: Sure, my name is David Harris.

ASSISTANT: Ok, please be on hold.

USER: Ok.

ASSISTANT: Sorry, we could not find any reservation on your name.

USER: Oh! It's ok, no problem. Thank you for your information.

ASSISTANT: Thank you for choosing us.