Can't! Theoretically, when swiping a card, the POS machine should ask whether to sign it according to the payment requirements of the card. There are three ways to pay by credit card: signature, password, password plus signature; The set payment method is password, but it doesn't need to be signed. However, at present, the domestic practice is that swiping a card with a bank card will be required to sign. This is mainly used when your account is wrong, PBOC personnel check your consumption details! Signing is mainly to check whether it is you; So, you can't get it back. POS(Pointofsales), which means "point of sale" in Chinese, is called point of sale information management system. It is a terminal reader equipped with bar code or OCR code technology, which has the cash register function of cash or barter bank. Its main task is to provide data services and management functions for commodity and media transactions, and to carry out non-cash settlement.