Authorization Only (Auth Only) is a special type of sale transaction. It authorizes an amount on a customers card but the item does not settle until a later time, sometime several days or weeks.
授權交易是一種特別的交易，他授權店家在一段時間內保留一筆金額在信用卡內，等到通常幾天或幾個星期後才真正的扣款或取消。
The purpose of an authorization only transaction is to reserve an amount against a card holder's available credit limit for a certain period of time.
此交易的目的是為了在消費者信用額度內保留一定的金額，已確保未來能夠支付此消費。
For example, a merchant may perform an authorize only transaction if an item ordered is out of stock. Then when the item is in stock, the merchant will then settle the transaction, essentially charge the card at that time.
例如，如果一個東西缺貨中，店家可以先產生一筆授權交易，等到貨物到了以後再扣款。
Another reason a merchant may do an authorization only transaction is when the exact amount to be charged to a card is not know. This is often used in the hotel industry. When a patron checks in to a hotel, their card is authorized for an amount greater than the length of their stay. However, the transaction is not settled until check out, where the hotel may include any incidentals you may want to charge to your room. At checkout the hotel enters the actual final amount and then settles the transaction and the card is charged.
另一個情況是，當你購買東西的時候還不知道應該花費多少時，店家會先保留一部份較高的金額在你信用卡中，等到你真正消費後才扣款。例如當你進入旅館時，在check in櫃臺，他會先扣一筆高於你應該要付的錢，這部份包含了一些你可能產生的消費額度，等到真正要離開時，如果沒有那一筆消費他就會退錢給你。
One caveat is that if an authorization only transaction is not settled within 24 hours, then the transaction can downgrade to a different rate category and the merchant may be surcharged a small fee. However, the benefits of using an authorization only transaction by a merchant usually outweigh any additional costs involved, since by doing the authorization the merchant is still guaranteed payment.
要注意的是：如果授權消費沒有在24小時內結算，該交易可能會要多產生一筆手續費。但是就算有手續費，他的好處就是能夠確保消費者有能力支付此項目，所以還是很常在生活上看到。
