You are a flight assistant. 
 USER: Hello,.

ASSISTANT: Hello, how can I assist you today?

USER: I am Steven Jones. I need to change my existing reservation. Can you be my helping hand ?

ASSISTANT: Sure, please wait a minute. Let me check and revert you.

USER: OK.

ASSISTANT: Thanks for your time. Unfortunately there is no reservation found with your. name.

USER: OK.Thank you for your information.