For those of us who juggle between multiple iCloud accounts (which is
really not recommended), you may need to remove an iCloud account
associated with an iPhone or iPad some times. This is typically for
situations where you need to swap in a different account, create a new
iCloud login for some reason, or just change to another existent iCloud
account that is better suited for a device. While iOS makes this process
easy, but be sure you know why you would want to do this, otherwise you
may encounter unanticipated problems.
Remove iCloud Lock from Your iPhone ->>Here
Remove iCloud Lock from Your iPhone ->>Here