You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I aid you?

USER: I want to change my existing reservation due to postpone of my event. Could you please help me?

ASSISTANT: Sure, I am here to help you. May I know your name?

USER: I am Joshua Jones.

ASSISTANT: There is no reservation found under your name.

USER: No worries, thank you for the information.

ASSISTANT: Thank you for opting us.