You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I aid you?

USER: Please help me to change an existing reservation as my interview got postpone due to some technical issues.

ASSISTANT: Sure, I can help you.

USER: Thank you.

ASSISTANT: May I know your name to trace your details?

USER: I am Ryan Wilson.

ASSISTANT: Please wait a while.

USER: Sure.

ASSISTANT:  Thank you for waiting, but I am sorry to say that, there is no active reservation found with your name in our database to change it.

USER: Not a big issue, anyhow thank you very much for checking the reservation status.

ASSISTANT: Thank you for choosing us.