Once you have approved an order, there is still a chance to edit or cancel the order. You need to look out for the order state "Waiting for production". During this time frame you can still edit and cancel the order. The usual need for this is to change the shipping address. Please see the screenshot below for an order in the state "Waiting for production". The cancel order option is still available.
Once an order moves to "In production" there is no longer an option to edit the details of the order or cancel it. SPOD will not refund orders that need to have details changed, or be canceled, once the order moves to "In production". The cancel order option is no longer available.