You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I help you?

USER: My name is James Walker.

ASSISTANT: James Walker, how can I help you?

USER: My holiday trip has been postponed, so I would like to change my existing reservation.

ASSISTANT: Sure, just hold on.

USER: Ok.

ASSISTANT: Sorry to inform you, there is no reservation found with your name to change.

USER: That's fine, thank you for your information.

ASSISTANT: You are welcome.