You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I help you?

USER: My meeting has been postponed.Can you please help me for changing the existing reservation?

ASSISTANT: May I know your name?

USER: Sure, my name is Gregory Gonzalez.

ASSISTANT: Gregory Gonzalez no reservations under your name.

USER: Ok. Thank you for your information.

ASSISTANT: Thank you for choosing us.