You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you?

USER: I am planning to change an existing reservation, due to some urgent work. Can you please help me out?

ASSISTANT: Sure, I am here to help you.

USER: Thank you.

ASSISTANT: May I know your name?

USER: I am Brenda Jones.

ASSISTANT: Please wait for a moment.

USER: Sure.

ASSISTANT: Sorry, there are no reservation found on your name.

USER: That's fine, thank you for your service.

ASSISTANT: Thank you for choosing us.