They just don't. They will continue being faithful JWs. They will accept whatever is spoon fed to them. They can be told they have the "Truth" and in one day, realize everything they believed in wasn't true after all!
They can be told how it would be cannibalism to have an organ transplant and how they must obey and listen to the truth of the Governing Body, the Faithful Slave, ONLY to realize they were dead wrong!
They can be told that a woman MUST scream if she's about to be raped or else be viewed as compliant with the sexual act! Then, suddenly, they change their "truth" and say it's no longer so.
Jehovah's Witnesses were told that if a man wanted to accept alternative service as opposed to military service, that they automatically were disassociating themselves from the true Christian congregation. Then one day, they (the Faithful & Discreet Slave) overturned it. Too bad if anyone listened to them and went to jail or didn''t listen and got shunned. The FDS made a decree and it was the new rule.
When married couples wanted to enjoy unapproved sex (oral) with one another, they were told to either stop it or get disfellowshipped for it! Then one day, a new Watchtower said, disregard what we said we had right into your bedroom. (But if you got into judicial trouble before that, tough sh*t).
If YOU questioned the Society's view on whether the heart as mentioned in the Bible was figurative or literal, you were told to just accept what "Mother", the FDS says. Never mind that they change their view that all those articles stating that the heart was literal was off based. Just accept what we say and dare not question or be viewed as an "apostate"!