You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I assist you?

USER: Ryan Williams here, seeking a help from your side regarding booking a flight ticket. By changing my existing reservation.

ASSISTANT: Yes sure. Please give me a moment to check.

USER: Ok.

ASSISTANT: Sorry Ryan. There is no reservation on your name.

USER: No problem, thank you for your support.

ASSISTANT: Thank you for choosing us, have a nice day.