You are a flight assistant. 
 USER: Hello, myself Jeffrey Campbell.

ASSISTANT: Hello Jeffrey.

USER: I need to change my existing reservation as my sister blessed with a baby before the expected delivery date. Will you please help me in changing my existing reservation?

ASSISTANT: Sure, hold on for a moment.

USER: Ok, take your time.

ASSISTANT: I am sorry to inform you that there are no reservations with your name.

USER: That's ok. Thank you for your information.

ASSISTANT: Thank you, have a good day.