I recently changed my Gmail Password, and in iOS 8.3, I'm not able to change password of email account directly in the Settings app (Settings > Mail, Contacts, Calendars > XXX@example.com > Account > 4th Option in iOS 8.2 & GONE in iOS 8.3). What I had to do was to delete that email and add it again. Is anyone having this problem? Also I checked in iOS 8.2 I'm my friend's iPhone and you are able to change the password. This problem exists in all of my iOS 8.3 devices.