You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I guide you today?

USER: Due to inconvenience of my work, I want to change my reservation. Can you please help me for that?

ASSISTANT: Sure, I am here to help you to change it.

USER: Thanks.

ASSISTANT: Can I have your name please?

USER: My name is Frank Johnson.

ASSISTANT: Ok, please wait for a while.

USER: Ok.

ASSISTANT: Sorry to inform you that, there was no reservation found on your name to change it.

USER: Anyway, thanks for the information.

ASSISTANT: Thank you for reaching us.