You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I assist you?

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

ASSISTANT: Sure, may I know your name?

USER: Sure, I am Donna Baker.

ASSISTANT: Please wait a minute.

USER: OK.

ASSISTANT: Sorry, no reservation found on your name.

USER: Ok, not an issue. Thank you for checking.

ASSISTANT: Thank you for opting us.