You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you?

USER: As my trip dates have been postponed, I would like to change my reservation.

ASSISTANT: Sure, can I know your name for checking the details?

USER: My name is Shirley Clark.

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

USER: Ok, thank you for your information.

ASSISTANT: Welcome.