You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Nancy Smith.

ASSISTANT: How may I help you?

USER: I need some help in my flight ticket changing, can you please help me in changing my flight ticket modification?

ASSISTANT: Sure, I am here to help you in modifying the ticket details.

USER: Thank you for accepting my request.

ASSISTANT: Sorry to inform you, there is no reservation found with your name in our database to change.

USER: Ok, not an issue with that one. I think it is not booked properly while I was booking. Thank you for your service and your quick information.

ASSISTANT: You are most welcome. Thank you for choosing us. Have a nice day.