You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I assist you?

USER: My trip is cancelled due to some problems in my family, so I need to cancel my ticket. Will you help me?

ASSISTANT: Yes, I will help you, may I know your name?

USER: My name is Carol Robinson.

ASSISTANT: I am sorry Robinson, no reservation has found for the name you have provided to cancel it.

USER: It's ok, thank you for the information.

ASSISTANT: Thank you for using our service, have a nice day.