Duplication is a very simple process, like copy/paste but for a whole ad. There is no relationship between the original ad and the duplicate ad at all. You can duplicate an ad from the home page, by right-clicking its entry and selecting Duplicate from the menu:
The Creative Factory will open with the original ad, but under a new ID. When you save this ad, it will not overwrite the original ad but will be saved as a new ad.
In the event that you want to duplicate the ad into a new Ad Format please do the following:
1) Create a new ad with the Ad Format you need
2) Copy and Paste the pages and or widgets from your original Ad.