Magento – Magento 1.9.3 Place Order not working

You can create a renderer for this as follow.

app\code\core\Mage\Adminhtml\Block\Sales\Order\Silverexchange.php

<?php
class Mage_Adminhtml_Block_Sales_Order_Silverexchange extends Mage_Adminhtml_Block_Widget_Grid_Column_Renderer_Abstract
{
    public function render(Varien_Object $row)
    {    
        $value =  $row->getData($this->getColumn()->getIndex());
        $order = Mage::getModel('sales/order')->load($value);
        $coupon_code = $order->getCouponCode();

        if($coupon_code == 'SE50') {
            $text = '<a href="'.Mage::helper('adminhtml')->getUrl('*/*/declaration', array("order_id" => $row->getId())).'">Silver Exchange Declaration</a>';
        } else {
            $text = '';
        }

        return $text; 
    }
}
?>

And in app\code\core\Mage\Adminhtml\Block\Sales\Order\Grid.php change following code under function protected function _prepareColumns()

$this->addColumn('silver_exchange', array(
    'header' => Mage::helper('sales')->__('Silver Exchange Declaration'),
    'index' => 'entity_id',
    'width' => '170px',
    'filter' => false,
    'sortable'  => false,
    'renderer'  => 'Mage_Adminhtml_Block_Sales_Order_Silverexchange',
));