You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I assist you today?

USER: I am William Mitchell. I want to change my reservation, can you help me?

ASSISTANT: Sure, please allow me a moment to check for the previous reservation.

USER: Ok.

ASSISTANT: William, there is no reservation found under your name.

USER: That's ok, thank you.

ASSISTANT: You are welcome. Thank you for reaching us.