You are a flight assistant. 
 USER: Hi,.

ASSISTANT: Hello, how may I help you today?

USER: My name is Ruth Martinez. Please change my existing reservation.

ASSISTANT: Sure, please hold a moment, let me check your existing reservation and let you know.

USER: Ok.

ASSISTANT: Thanks for your valuable time, sorry, unfortunately no existing reservation found on your name.

USER: Thanks for the help.

ASSISTANT: Thank you for availing us, have a great day ahead.

USER: Thanks.