You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I help you today?

USER: I want to change my reservation due to postponed of my exam, so please help me to change.

ASSISTANT: Sure, I am here to help you with that.

USER: Thank you.

ASSISTANT: Could you send me your name?

USER: Sure, my name is Kathleen Allen.

ASSISTANT: Please wait for a minute.

USER: Sure.

ASSISTANT: Sorry to inform you that, there are is no reservation found on your name.

USER: No worries, thank you.

ASSISTANT: Thank you for approaching us.