You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I assist you?

USER: I am Michelle Thomas. Can you help me in changing my existing reservation?

ASSISTANT: Sure, may I know your name please? Ok, please hold on.

USER: I have mentioned above.

ASSISTANT: Sorry Thomas, there is no reservations found on your name. Thank you, for contacting us.

USER: Thank you for the quick response.