You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I assist you today?

USER: I want to change my existing reservation due to sudden postpone of my exam dates.

ASSISTANT: Sure, we are here to help you.

USER: Thank you.

ASSISTANT: Can I have your name to proceed further?

USER: I am Barbara Smith.

ASSISTANT: Ok, please wait a moment.

USER: Sure.

ASSISTANT: Thank you for your time, unfortunately no reservation found on your name.

USER: Ok, no problem. Thank you for your information.

ASSISTANT: Thank you for reaching us.