If you want to modify or delete existing transactions in BUSY, you can follow these steps:
Step 1: Go to the Transaction menu and choose the voucher type that you want to modify or delete, such as Sales, Purchase, etc. You can also open that invoice from the list of vouchers.
Step 2: Click on Modify and open the voucher that you want to change or remove.
Step 3: Make the necessary changes and save them again.
Step 4: To delete the voucher, click on Delete button or press F8 after opening it.
Note: Take latest backup of your data before making any changes.