$Invoice->setDate('2015-06-08'); $LineItem = new ChargeOverAPI_Object_LineItem(); $LineItem->setItemId(3); $LineItem->setLineRate(29.95); $LineItem->setLineQuantity(3); $LineItem->setDescrip('Add this new line item to the invoice.'); $Invoice->addLineItems($LineItem); // To keep the existing line item, you have to pass the line_item_id $LineItem = new ChargeOverAPI_Object_LineItem(); $LineItem->setLineItemId(2575); $Invoice->addLineItems($LineItem); $resp = $API->modify($invoice_id, $Invoice); /* print("\n\n\n\n"); print($API->lastRequest()); print("\n\n\n\n"); print($API->lastResponse()); print("\n\n\n\n"); */ if (!$API->isError($resp)) { $invoice_id = $resp->response->id; print 'SUCCESS! Invoice # is: ' . $invoice_id; } else { print 'Error saving invoice via API' . "\n"; print 'Error message was: ' . $resp->code . ': ' . $resp->message . "\n"; print "\n\n\n\n"; print $API->lastRequest(); print "\n\n\n\n"; print $API->lastResponse(); print "\n\n\n\n"; }