You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I assist you?

USER: My client meeting have postponed so, I want to alter my booked ticket dates. Can you please help me to change my existing reservation?

ASSISTANT: Sure, we can help you. Can you please tell me your name?

USER: Sure, I am David Jones.

ASSISTANT: David, with the information of your details there is no reservation found.

USER: That's fine. Thank you for your time.

ASSISTANT: Thank you.