From SE10, you can find out which objects are in the transport request you want to undo. Assuming these are ABAP programs, from SE38 you can call up prior versions.
From the list, select the prior version you want to retrieve.
Activate this version. I think this will trigger a transport request, but I can't recall for sure. If not, manually create a transport request in SE10 and add the object to it. However, it's probably automatically triggered. Release the request and transport through the landscape as you normally would.
Voila. You have reverted the change. You can also use the Remote Comparison tool in this screen to compare versions between systems.
--Matt