You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can I help you now?

USER: I am Larry Taylor. I want to change my existing reservation because my convocation dates have been postponed. Can you help me out?

ASSISTANT: Sure, I will help with that.

USER: Ok.

ASSISTANT: Please wait for a moment, while I check for the reservation.

USER: Take your time.

ASSISTANT: Thanks for waiting, Sorry to inform you there is no any reservation found on your name.

USER: Not an issue. Thank you for kind information.

ASSISTANT: Thank you, have a nice day.