You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I assist you today?

USER: Owing to an emergency, I want to change an existing reservation, so please help me in changing the reservation.

ASSISTANT: Sure, may I know your name please?

USER: I am Mary Taylor.

ASSISTANT: Ok, please wait for a moment.

USER: Ok.

ASSISTANT: Sorry, there was no reservation found with your given name.

USER: Not an issue. Thank you.

ASSISTANT: Thank you for opting us.