You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I would like to change my existing flight reservation that has been booked earlier this week.Could you please help me in re-modifying my dates in the reservation?

ASSISTANT: Ok, please provide me your name on which the ticket is reserved. So I can check.

USER: Myself Virginia Perez.

ASSISTANT: Ok, please wait a moment.

USER: Sure.

ASSISTANT: Thank you for waiting, the reservation is not found which you need in our records.

USER: That's fine, thank you.

ASSISTANT: Thank you for choosing our agency.