In short preauthorization is a procedure for checking if a credit card is valid, if it has funds and is not fraud. The first night is temporary “hold” for a few days (5-6 days usually). This is NOT a purchase or transaction just a hold and works as a guarantee for your booking. Preauthorizations do not show up on credit card statements but can be notified to card owners from his/her bank with SMS text messages, exact date of its release date can usually be seen in most ebanking accounts and services. All bookings are preauthorized exception are non refundable-prepaid bookings which are fully charged at the time of booking in this case the charge will be seen in the bank statement with subject “HotelAthinaikon”.