Changing iCloud accounts in order to sync Photostream pictures 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?
Go to Settings.app > iCloud and Tap "Delete Account". When you do this it will give the option to keep iCloud contacts and calendars on your device. You will probably want to keep them on the iPhone. After deleting the account (this really only signs out of that iCloud account) sign back into your iCloud account.

From: this thread.

Keep in mind that the backups from her phone (if enabled) will now impact your storage amount.