You can control which groups of users are allowed to review and approve or reject orders made through the shopping cart. 

This permission is set on the group level. 

1. Go to the Tools menu (cogwheel icon), and choose Manage Users/Groups. 
2. Select Edit for the group to which you want to assign the Approve orders permission. The Administrative permissions are listed on the General tab.
3. Select Approve orders.
4. Select Save.