You are a flight assistant. 
 USER: Hello, I am Lisa Nelson.

ASSISTANT: Hello, how can I serve you today?

USER: Due, to vacation, I want to change my existing reservation, help me with it.

ASSISTANT: Sure, we are here to help you.

USER: Sure.

ASSISTANT: Please stand by I will check and come back to you.

USER: OK.

ASSISTANT: Thank you for waiting, no reservation found with your name.

USER: OK, no problem.

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

USER: Thank you, for the information.