This has been once posted by a dev (on disney playdom forums):
1. Replay the tutorial up until after you get to the faction choice screen.
2. Choose a side and a name.
3. Complete the tutorial, up until the first chapter starts. You can exit after opening the play window, no need to start the chapter.
4. Go to settings.
5. See Login and sign in with your login.
6. The game will ask you to choose between syncing your old base and your new base.
Take care on Step 6. This decides whether your sync data will be overwritten(=lost) or used.
Source:https://www.playdomforums.com/showthrea ... layerID%29
Support Link:https://www.playdomforums.com/forumdisp ... -Commander