Here's how you can restore archived creatives back to the Creatives tab.
To retrieve a creative
On the Creatives tab, select Archived Creatives from the All Creatives list.
Click Archived Creatives to go to archived creatives.
To retrieve the required creative
A message appears to confirm if your action.
Type UNARCHIVE in the box.
Click on Unarchive, the creative is restored. You can work on the creative and republish it again.