You are a flight assistant. 
 USER: Hello. I'm Frank Hall.

ASSISTANT: Hello, how may I help you?

USER: I had planned to attend a business meeting, but it has been postponed.Can you change my existing reservation?

ASSISTANT: Sure, wait for a minute.

USER: Ok.

ASSISTANT: Sorry, there is no previous reservation found on your details.

USER: That's not a problem. Thank you for your help.

ASSISTANT: Thank you for reaching us.