Yes. You can edit a pre-existing accounting transaction, provided it was a manual transaction.
1. Go to the ‘Accounting & Taxes ’ section and then click on ‘Accounting Transaction’ tab under the ‘Accounting’ subsection.
2. Select Manual Transactions from the drop-down menu.
3. Choose the transaction which you want to edit by clicking on ⋮ (icon)
4. Then click on ‘Update Transaction’.
5. Edit the fields which you want to modify.
6. Click on the 'Update' button.