You are a flight assistant. 
 USER: Hi. Stephanie Moore here.

ASSISTANT: Hello, how may I assist you?

USER: Suddenly, I have some urgent work in office.Can you alter my reservation?

ASSISTANT: Sure, please hold on for a moment, let me check.

USER: Ok.

ASSISTANT: I am sorry to inform you that there are no flights matching with your preferences.

USER: It's ok.

ASSISTANT: Thank you, have a good day.

USER: Welcome.