My spouse and I both have iPhones. We use 1 apple ID for the iTunes store. She has a different apple ID for iCloud. If her phone was lost could I use her apple ID in the find my iPhone app on my phone to locate her phone? Is the app separate from the find my iPhone setting under settings/iCloud? If they aren't separate could logging in using her apple ID on the app on my phone mess up my phone/settings/iCloud, etc? Thanks.