You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: my name is William Wright.

ASSISTANT: How may I assist you?

USER: I want to change my existing reservation, can you please help?

ASSISTANT: William Wright, please allow me to check with your existing reservation for a moment.

USER: Sure.

ASSISTANT: Sorry to tell you, there is no active reservation found by your name.

USER: No problem, thank you.

ASSISTANT: Thank you for utilizing our services.