You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I assist you?

USER: Have a concern regarding the flight reservation, can you help me with that?

ASSISTANT: Sure, I will help you. Your good name please?

USER: There is a sudden change in my planned, can you cancel my reservation as I can re-plan my trip? My name is David Campbell.

ASSISTANT: Sure, please standby.

USER: Ok, please take the time you need.

ASSISTANT: Thank you for waiting. I am sorry to inform you that, there is no reservation found on your name to cancel.

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

ASSISTANT: Thank you for contacting us.