You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: My name is Nicole Campbell.

ASSISTANT: Campbell, how can I help you?

USER: Suddenly my trip plan is changed.So I want to cancel my reservation. Can you please help me for that?

ASSISTANT: Please wait for a moment.

USER: Ok.

ASSISTANT: There is no reservation with the details you have provided.

USER: Thank you for helping me.

ASSISTANT: You are welcome.