You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I help you?

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

ASSISTANT: May I know your name to check your reservation?

USER: My name is James Carter.

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

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

ASSISTANT: Thanks for choosing us.