Change iCloud User/Password account on iPhone 4
Through Verizon, I transferred my iPhone 4 to another family member. I purchased an iPhone 4s from Verizon. The iPhone 4 now (as it did before) has my iPhone 4s iCloud Apple ID and Password. Other family member also has an (independent) Apple ID and Password.
How do I change the iPhone 4 iCloud ID/Password to other family member, the current owner?
As I have read a lot of unhelpful info on this subject, I want to be clear that I an talking about 2 different Apple iPhones (4 and 4s) which need separate and independent iCloud accounts. Any iCloud activity (including billing) will be unique to each iPhone. I also have other iDevices which correctly access my iCloud account.