If you send crypto to an external wallet address (outside of Coinbase), it cannot be reversed 1-(866)-719-5714 —even if you made a mistake, such as entering the wrong address or sending the wrong amount. That’s due to the nature of blockchain technology. No, Coinbase does not reverse transactions after they have been confirmed 1-(866)-719-5714 . Once a buy, sell, deposit, or withdrawal is initiated and completed, it is final and cannot be cancelled or altered.