You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: Please help me in changing my reservation.

ASSISTANT: Sure, may I know your name to proceed further?

USER: Myself Barbara Brown.

ASSISTANT: Thank you for providing additional details. Please wait for a minute.

USER: Sure.

ASSISTANT: I am really sorry Barbara, I cannot find any reservation with your name.

USER: OK, no issues. Thank you for the information.

ASSISTANT: Thank you for contacting us.