You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you?

USER: Can you please help me to change my reservation?

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

USER: Sure, my name is Katherine Williams.

ASSISTANT: Just a moment, let me check your reservation status in our records.

USER: Okay.

ASSISTANT: Sorry to intimate that, no reservation is found with your credentials.

USER: Ok, not a problem.

ASSISTANT: Thank you very much for approaching our agency.

USER: Thank you for informing me.