Here are the steps for retrieving a released request.
1. Use SE10 to create a new request which is the same type with that old request (Workbench or Customizing).
2. Go to "display" this new one, point to that and choose "Include Objects"
3. When this dialog box appears, choose " Object list from request" (in radio button on the left site)
4. Then type the old request number into this box and press Enter
Now, all objects in the old released request are in the new one. You can use this one to modify then release and transport again.