To make changes to the items on your Sales Order, click on Edit Order and make the necessary changes permitted based on the Order Stage. In the Draft & Active stage, you can make any changes to the items on the Sales Order. In the Finalized (when Invoiced/paid) and Fulfilled stage, you can only add items or increase the quantity of existing items, but not remove items or deduct the quantity of existing items. If a Finalized order has not yet been involved/paid for, you can then remove items or deduct the quantity of the items. Click here for more information.