I have Ipad and an Android phone. My issue for restarting was Facebook. After deleting the app from your device and clearing storage like iCloud (you will have to find directions for this crap, is turned off on my devices) then go to Facebook, settings, apps and websites and delete the game(s) you want to restart. Reinstall and play.

And do not give me crap about not storing on the "Cloud" - every site I've checked owns what ever you upload for eternity. Read the Policies.

Go to Facebook, Settings, Active Tab and remove the games you want to restart. Delete the game, reinstall on your device. You'll need to empty ICloud if on Apple. Not sure if Android has same. Facebook was the biggest issue for me. Hope this helps. I couldn't find how to do it either, then I went straight to FB.