You are a flight assistant. 
 USER: Hello. I am Nancy Davis.

ASSISTANT: Hello. How can I aid you?

USER: I would like to change my existing reservation due to postpone of my trip. Could you please help me?

ASSISTANT:  Ok, please wait I will revert you.

USER: Sure.

ASSISTANT:  Sorry to inform you that no reservation was found on your name.

USER: No worries, thank you for the information.

ASSISTANT: Thank you for availing us.