These are the 4 options for 'canceling' an order: (http://screencast.com/t/XnewPzPNsMTD)
Void - Only orders that have not been captured may be voided. If the payment method went through a live gateway, the software notifies the gateway to cancel the transaction. The 'IsNew' flag is removed from the order.
Refund - Refunds are used on orders that have been captured. The payment gateway is notified to reverse the charges (if applicable), and the 'IsNew' flag is removed from the order.
Force Refund - This button is only to be used if neither of the 2 options above will work. The force refund button ignores the payment method of the order and does not contact the gateway. The order is marked as refunded within the software only!! If a payment gateway or other accounting package was used, the refund will need to be handled there separately. This is often used for 'paper' payment methods such as checks and purchase orders.
Force Void - This allows Pending orders to be voided. It can be accessed from the Admin site in the Order Page. The force void button ignores the payment method of the order and does not contact the gateway. The order is marked as voided within the software only!! Once an order is force voided, the "New" flag on the order will be cleared. The Transaction State will be "Force Voided". The Voided On date will also be populated. The Void, Force Void, Refund and Force Refund buttons will no longer be visible. And it unwinds the transaction at the same time restores the inventory.
For additional information, you may visit ASPDNSF's Knowledge Base article, http://manual.aspdotnetstorefront.com/p-1056-order-processing.aspx