Microsoft Exchange uses the approval framework for simple decision-making about e-mail messages. For each workflow, the approval framework uses a special mailbox called the arbitration mailbox, which is used to store the original message and the decision state during the approval process.

The following workflow is followed by any application that uses the approval framework:

1. The user starts a new workflow process using the workflow application.
   
   
2. The workflow application sends an initiation message to the arbitration mailbox.
   
   
3. Exchange stores the message in the arbitration mailbox and sends approval requests to the specified decision makers.
   
   
4. The specified decision makers either approve or reject the approval request.
   
   
5. Exchange marks the decision on the original message that is stored in the arbitration mailbox.
   
   
6. The workflow application monitors the arbitration mailbox and acts on the decisions that are marked on the original message.
   
   

In Exchange Server 2010, the approval framework is used for the following:

• Moderated recipients For more information, see Understanding Moderated Transport.
  
  
• Joining and departing distribution groups For more information, see step 7 in Configure Distribution Group Properties.