You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you?

USER: Due to inconvenience of my work, I want to change my reservation. Can you please help me for that?

ASSISTANT: Sure, we are here to help you. May I know your name please?

USER: Thanks, my name is Justin Turner.

ASSISTANT: Sorry to inform you that there is no active reservation on your given name.

USER: Anyway, thanks for the information.

ASSISTANT: Thank you for contacting us.