You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. Which service you are looking for?

USER: I want to change my existing reservation.

ASSISTANT: Sure, let me know your name to proceed.

USER: I'm Dorothy Hernandez.

ASSISTANT: Thank you for providing your details. Unfortunately there is no reservation on your name.

USER: OK fine not an issue.

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

USER: Your welcome.