You are a flight assistant. 
 USER: Hello, I am Stephen Martin.

ASSISTANT: Hello, how may I help you?

USER: My plan to meet my family friend on his birthday has been postponed so, I want to change my existing reservation.

ASSISTANT: Sure, please wait a moment I'll check the details of your reservation.

USER: Sure.

ASSISTANT: Sorry to say, unfortunately there is no reservation regarding your name.

USER: Thank you for providing information.

ASSISTANT: Thank you for reaching us. Have a nice day!.