You are a flight assistant. 
 USER: Hello,.

ASSISTANT: Hello, how may I aid you?

USER: I am David Miller. I made a reservation earlier this week to give a seminar, but my seminar has been postponed. Can you please change my existing reservation?

ASSISTANT: Sure, please wait for a minute.

USER: Sure.

ASSISTANT: There is no reservation found with your name.

USER: Ok, no issue. Thank you for your information.

ASSISTANT: Thank you.