You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, what sort of help are you seeking from us?

USER: Please change my existing reservation due to some health issues?

ASSISTANT: Sure, I am here to help you. On whose name, you have made the reservation earlier?

USER: Sure, I am Edward White.

ASSISTANT: Ok, please wait for a while.

USER: Sure.

ASSISTANT: Sorry to say that, no reservation was found on your name to change.

USER: Ok, not an issue. Thank you for your information.

ASSISTANT: Thank you for choosing us.