Magento: How to change order status programmatically?

Here, I will show you, how you can change your order status programmatically (with PHP coding).
First, you need to load your order.
If you have order id, you can load order in the following way:-
$orderId = YOUR_ORDER_ID;
$order = Mage::getModel(‘sales/order’)
->load($orderId);
If you have order increment id, you can load order in the following way:-
$orderIncrementId = YOUR_ORDER_INCREMENT_ID;
$order = Mage::getModel(‘sales/order’)
->loadByIncrementId($orderIncrementId);
Now, here is the code to change order status:-
/**
* change order status to ‘Completed’
*/
$order->setState(Mage_Sales_Model_Order::STATE_COMPLETE, true)->save();
Similarly, you can change the order status to pending, processing, canceled, closed, holded, etc.
/**
* change order status to ‘Pending’
*/
$order->setState(Mage_Sales_Model_Order::STATE_NEW, true)->save();
/**
* change order status to ‘Pending Paypal’
*/
$order->setState(Mage_Sales_Model_Order::STATE_PENDING_PAYMENT, true)->save();
/**
* change order status to ‘Processing’
*/
$order->setState(Mage_Sales_Model_Order::STATE_PROCESSING, true)->save();
/**
* change order status to ‘Completed’
*/
$order->setState(Mage_Sales_Model_Order::STATE_COMPLETE, true)->save();
/**
* change order status to ‘Closed’
*/
$order->setState(Mage_Sales_Model_Order::STATE_CLOSED, true)->save();
/**
* change order status to ‘Canceled’
*/
$order->setState(Mage_Sales_Model_Order::STATE_CANCELED, true)->save();
/**
* change order status to ‘Holded’
*/
$order->setState(Mage_Sales_Model_Order::STATE_HOLDED, true)->save();
You can also cancel an order in the following way:-
if($order->canCancel()) {
$order->cancel()->save();
}
Hold an order:-
if($order->canHold()) {
$order->hold()->save();
}
Unhold an order:-
if($order->canUnhold()) {
$order->unhold()->save();
}