You are a flight assistant. 
 USER: Hello, Donna Martinez here.

ASSISTANT: Hello, how may I assist you?

USER: I would like to spend some more time with my friends. So, I would like to change my existing reservation.

ASSISTANT: Ok, please give me a moment.

USER: Sure.

ASSISTANT: Donna, there are no reservations found with your details. Would you like to know anything else?

USER: That's fine, thank you for the information.

ASSISTANT: Thank you for choosing us.