[Glossary](https://blnkfinance.com/glossary) Reversal # What is a reversal? Reversal A reversal is taking back a payment you already originated, using the rail’s reversal process. In ACH, the ODFI can reverse a credit sent in error under Nacha rules and deadlines. It is not a customer refund and not a return. Your book still needs a new post the other way. ## How does a reversal work? You discover a duplicate or a wrong amount after the credit left. The rail lets you file a reversal for a short window, with a reason. The receiving bank may still reject it. When it lands, the omnibus comes back. The wallet must come back too. ## Reversal vs refund vs return A refund is you paying the customer back on purpose. A return is the other bank sending the item back. A reversal is you asking the network to unwind your own send. Call the API by the event you have, not by the word the support ticket used. ## What if the rail refuses? You still owe a correction in the book if you already committed. Collect from the wallet, or take the loss on an expense account. Do not delete the original credit. ## How it works with Blnk If the original is inflight, void it. If it applied, [refund](https://docs.blnkfinance.com/transactions/refunds) it or post the opposite path and keep the rail reversal id as the reference parent. Related terms - [ACH return](https://blnkfinance.com/glossary/ach-return) - [Refund](https://blnkfinance.com/glossary/refund) - [Transaction](https://blnkfinance.com/glossary/transaction) - [Settlement](https://blnkfinance.com/glossary/settlement) - [ACH credit](https://blnkfinance.com/glossary/ach-credit)