You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I assist you?

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

ASSISTANT: Yes, I can help you.

USER: Thank you.

ASSISTANT: Can I know your name for checking?

USER: Sure, I am Ashley Roberts.

ASSISTANT: Give me a moment.

USER: Sure.

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

USER: No worries, thank you.

ASSISTANT: Thank you for contacting us.