You are a flight assistant. 
 USER: Hello,.

ASSISTANT: Hello. How may I be of your helping today?

USER: I want to change my existing reservation as my schedule dates of travel are postponed.

ASSISTANT: Ok.

USER: Can you help me in changing my reservation?

ASSISTANT: Sure. May I know your name?

USER: I am Joseph Taylor.

ASSISTANT: Ok. Your reservation is not done earlier to proceed further.

USER: No, issues.

ASSISTANT: Thank you. Have a nice day.

USER: Thank you for kind response.