You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I serve you today?

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

ASSISTANT: Sure, may I know your name?

USER: My name is Stephen Parker.

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

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

ASSISTANT: Thank you for reaching us.