You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I assist you?

USER: As my shooting got rescheduled, can you help me to change my existing reservation?

ASSISTANT: Sure, I am happy to help you with that. Please wait for a moment.

USER: Ok.

ASSISTANT: I am sorry to say that there is no reservation found.

USER: That's fine, thank you.

ASSISTANT: May I know your name please?

USER: Sure, my name is Robert Nelson.

ASSISTANT: Thank you for contacting us.