You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I aid you?

USER: I want to change my existing reservation. Can you help me in that?

ASSISTANT: Sure, I am here to help you.

USER: Thank you.

ASSISTANT: May I know your name to proceed further?

USER: Helen Williams.

ASSISTANT: Ok, please wait.

USER: Sure.

ASSISTANT: Thank you for waiting, No reservation was found on your name.

USER: Ok, no problem. Thank you.

ASSISTANT: Thank you for availing us.