You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you?

USER: This is Stephen Gonzalez. Could you please help me to change my existing reservation?

ASSISTANT: Sure, please wait a minute.

USER: OK.

ASSISTANT: Sorry Stephen, there is no reservation found with you name.

USER: That's fine. Thank you for the information.

ASSISTANT: Thank you for approaching us.