You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you today?

USER: I want to change my existing reservation. Could you help me with that?

ASSISTANT: Sure, I am here to help you.

USER: Thank you.

ASSISTANT: On which name ticket has been reserved?

USER: Brandon Turner.

ASSISTANT: Please wait for a moment.

USER: Ok.

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

USER: That's ok, no problem. Thank you.

ASSISTANT: Thank you for contacting us.