You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, may I know your name?

USER: My name is Amanda Robinson.

ASSISTANT: Robinson, tell me how may I help you?

USER: Suddenly my trip plan is changed.So I want to cancel my reservation.

ASSISTANT: Ok, just wait for a while.

USER: Ok.

ASSISTANT: I am sorry there is no reservation found with your name to cancel.

USER: Thank you for helping me.

ASSISTANT: Most welcome.