To do this , you would need to have third device. (maybe an old iPod, phone? Maybe a parent's iPhone or iPad?) It would have to be a device that has never had a storm ID set up.
If you can find a third device you can transfer your storm ID and games off your old device by using a storm 8 game.
Transfer Thread
Then your sister and download new games .
You can also try sending an email to
support@teamlava.com explaining that you are giving away your old device and you would like your storm ID removed so no one else can play your games.