You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I assist you for the day?

USER: I am Jennifer Hernandez. I want to change my existing reservation. Could you help me in booking?

ASSISTANT: Sure, I am mirthful to help you with that reservation change. Please hold for a moment, let me check your previous reservation status.

USER: OK.

ASSISTANT: Thank you for waiting. There is no active reservation found with your name in our reservation list to change it.

USER: That's ok, no problem. Thank you.

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