want to change email and password on cloud account without loosing data
How do I change my iCloud email address and password without loosing all current data, aps, etc?
iPad, iOS 5.1.1
This explaines how to change the email address associated with your iCloud ID: http://support.apple.com/kb/HT5621. (Your iCloud ID is also an Apple ID.)
This explains how to reset the password: http://support.apple.com/kb/PH2617.
This explains what to do after making these changes: http://support.apple.com/kb/HT5796.
Before starting, if you have Find My iPad turned on, turn it off.