You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you at present?

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

ASSISTANT: Sure, may I know your good name?

USER: I am Joshua Hall.

ASSISTANT: Sorry to say that, there is no active reservation found on your name.

USER: No problem, thanks for the information.

ASSISTANT: Thank you for choosing us.