I have three iOS devices that I would like to have Photostream sync across. Right now, the iPhone 5 and iPad 2 sync because they are on the same iCloud account, but my wife's iPhone 4 doesn't sync - because it signed into a different iCloud account. I'm told all 3 iCloud accounts need to be signed into the same account.
I need to change my wife's iCloud Apple ID on her iPhone 4 to mine. When I go to Settings, iCloud, Account, her Apple ID is grayed-out, so I can't make changes.
How can I change the iCloud account on the iPhone 4?