You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can I aid you?

USER: I need to change my existing reservation, can you please help me with that?

ASSISTANT: Sure, I am here to help you.

USER: Thank you.

ASSISTANT: May I know your name please?

USER: Joseph Turner here.

ASSISTANT: Ok, please wait a minute.

USER: Sure.

ASSISTANT: Thank you for waiting. Sorry, I did not find any reservation by your name in our database.

USER: Ok, no problem. Thanks for your information.

ASSISTANT: Thank you for reaching us, have a good day.