In SAP Business One you can never remove some wrong transaction, instead you have to reverse it.
Just like that we can display the credit balance with a negative sign and how to set it up. This isn’t the only option offered by SAP Business One regarding negative amounts. SAP Business One also allows users to define whether to allow negative amounts for reversal transaction posting.
When reversing transactions by creating a journal entry, an accountant may decide either to switch the debit and credit so that they are opposite to the original transaction or to keep debit and credit on the same side but using negative signs. If users prefer the second way, “allow negative amounts for reversal transaction posting” can be a nice choice. Go to Administration > System Initialization > Company Details and click Basic Initialization tab. Click “allow negative amounts for reversal transaction posting”. The choice can be changed anytime.