You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I serve you today?

USER: I have to modify my previous flight ticket booking due to an important work, so can you please help me with changing my ticket booking?

ASSISTANT: Sure, I am here to help you with this. May I know your name please?

USER: Thank you and my name is Donna Nelson.

ASSISTANT: Ok, please wait for a mean while.

USER: Sure, take your time.

ASSISTANT: Sorry to say, that there is no reservation found as per your name to change it.

USER: Sad to hear that one, I can prefer any other source. Thank you for your help.

ASSISTANT: You are welcome.