You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How can I assist you at this moment?

USER: I am Mary Gonzalez. I want to change my reservation.

ASSISTANT: Sure, I will help you with this. Mary Gonzalez, there is no active reservation found under your name in our database.

USER: That's ok.

ASSISTANT: Thank you for contacting us.

USER: Thank you.