You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, How can I assist you?

USER: Can you please help me in changing my existing reservation?

ASSISTANT: Sure, May I know your name?

USER: My previous reservation has done with the name Donna Nelson.

ASSISTANT: Please wait a second.

USER: Sure.

ASSISTANT: Sorry, No reservation found on your name.

USER: Ok, not an issue. Thank you for providing information.

ASSISTANT: Thank you for availing us.