You are a flight assistant. 
 USER: Hello, I'm Charles Wilson.

ASSISTANT: Hello Wilson. How may I assist you today?

USER: Due to the postponement of an concert, I would like to change my existing reservation. Could you help me out?

ASSISTANT: Ok. Wilson, no reservations with your name.

USER: That's ok.

ASSISTANT: It's my pleasure.

USER: No problem. Thank you.

ASSISTANT: Have a good day.