You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I aid you today?

USER: Linda Phillips here. I need to change my existing reservation due to some problem. Can you please help me in that?

ASSISTANT: Sure, I am glad to help you.

USER: Thank you.

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

USER: That's ok, no problem. Anyway thank you for the information.

ASSISTANT: Welcome, have a nice day.