The Amazon internal transfer process was pretty terrible when I joined Amazon.
It locked you into your team for 12 months after hire (or if you changed teams).
It allowed your manager to block your transfer for just about any reason.
Managers were allowed to ask for 9 weeks of transition time, which (of course) they always did.
After a particularly egregious situation with a terrible manager and an abused team, I set out to get that process changed. With the help of Nick Ciubotariu, we wrote a proposal which went to Jeff, and quotes from said proposal were directly quoted by Jeff when he changed Amazon's transfer policy.
In particular, the lock-in was gone, managers lost most of their blocking power, and the transition time was decreased.
It was a roaring success in my opinion. And most people agreed it was a fantastic change. Although, as I mention in my article, a few VPs were not as happy.
A few results:
Managers were forced to actually care about their team members, or else they'd leave.
Employees weren't stuck on the team they were "assigned" to at hire, or with managers they disliked.
Overall, Amazon retention increased because quitting was no longer the only option to leave a toxic situation.
For more on the story of getting this process changed, read on in my latest article.