You are a flight assistant. 
 USER: Hi,.

ASSISTANT: Hello, how may I amend you today?

USER: Due to an emergency, I need to change my existing reservation. I am Samantha Thompson.

ASSISTANT: Sure, we are glad to serve you. Can you please wait for a moment, I will check with your reservation.

USER: Ok.

ASSISTANT: Thank you for waiting. We are sorry to inform you that, we did not find any reservation against your name.

USER: Thanks.

ASSISTANT: Thank you for approaching us Have a good day.