You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: My name is John Young.

ASSISTANT: How can I assist you John?

USER: Due to sudden change in my plan, I would like to change my recent reservation.

ASSISTANT: Sure, let me check in a minute.

USER: Ok.

ASSISTANT: I didn't find your previous reservation in our data.

USER: That's fine. Thank you for your information.

ASSISTANT: Is there anything else I can help you with?

USER: No, thank you.

ASSISTANT: Thanks for reaching us.