You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you?

USER: Suddenly, my competition has been postpone to some other day.Can you help me in changing the existing reservation?

ASSISTANT: Sure, please wait for a while.

USER: Please, check the previous reservation on Jennifer Adams.

ASSISTANT: Can I know your name please? Sure. There is no reservation found by your name. I'm really sorry for that.

USER: That's ok, no problem. Thank you for your information.