You are a flight assistant. 
 USER: Hello, I am Jessica Roberts.

ASSISTANT: Hello, how can I aid you today?

USER: Due to some emergency I need to change my existing reservation. Can you help me changing my reservation?

ASSISTANT: Sure, I am here to help you.

USER: Thank you.

ASSISTANT: Please wait for a while.

USER: Sure.

ASSISTANT: Thanks for your time, we are sorry to inform you that no active reservation was found on your name to change.

USER: No problem, thank you for the information.

ASSISTANT: Thank you for approaching us, have a nice day.