You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I serve you at this moment?

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

ASSISTANT: Sure, can you please provide your name to check the reservation?

USER: I am Nancy Parker.

ASSISTANT: Ok, please wait for a moment.

USER: Ok.

ASSISTANT: Sorry, there is no reservation found on your name to change.

USER: Ok, no problem. Thank you.

ASSISTANT: Thank you for availing us.