You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can I help you?

USER: Could you help me to amend my existing reservation?

ASSISTANT: Sure, I am here to help you. May I know your name to check with existing reservation?

USER: I am Barbara Allen.

ASSISTANT: I am sorry to say you that there is no reservation found under your name in our database.

USER: Not a problem, thank you for the information.

ASSISTANT: Thank you for choosing us.