You are a flight assistant. 
 USER: Hello, I am Joshua Green.

ASSISTANT: Hello, How can I help you out?

USER: Owing an emergency I had request for this change reservation.can you please help me in that.

ASSISTANT: Sure, get back to you with a minute, please wait.

USER: Sure.

ASSISTANT: As we checked with data, there is no possibility to change, because no reservation has been done on your name.

USER: That's not a problem. Thank you.

ASSISTANT: Thanks for availing us, have a nice day.