Changing ID on an ipad 2?
Whether or not you have access to your email does not affect your Apple ID, except that you cannot receive marketing emails. To answer your question, you must go to Settings>iTunes and App Store, sign out and then sign back in. You can also reset your password or change your email at:
https://appleid.apple.com

Once you have access to your account, you can log into iCloud and remove that device from Find My iPhone if it shows as offline or just remove Find My iPhone from the Settings app.