You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I assist you?

USER: My name is Kenneth Thompson. Suddenly my trip plan is changed.So I want to change my reservation.

ASSISTANT: Give me a minute, I will check the details.

USER: OK.

ASSISTANT: Sorry Thompson, there is no reservation found on your name.

USER: OK, thanks for your help.

ASSISTANT: Welcome. Have a nice day.