You can delete orders when they are in the Cancelled status. To delete an order first change the order status to Cancelled and then delete the order. You must be an administrator to perform this action.
To cancel an order from the Neto Dashboard, navigate to Sales Orders > View Orders and and filter the orders to the order(s) you want to delete is displayed in the list.
Select an order by checking the box on the left, and in Bulk Actions select Cancelled from the Change Order Status drop down. Then click on Apply.
The product(s) will now be moved back into stock and be available for purchase again.