In Blackbaud Sphere, Chargebacks are used for payments that have already been reversed by the cardholder's bank. Selecting Chargeback on a transaction you are about to delete will not cause a reversal of the transaction. This solution covers any issue where the Chargeback option is disabled for the entire account, and therefore cannot be selected.
It is not possible for Organizations to issue Chargeback reversals themselves or mark a transaction as a Chargeback, unless they are using a custom payment processor. If the transaction needs to be reversed, delete the transaction to trigger a reversal.