This question already has an answer here:
Is it possible to change the "user2612587" display name and also change the picture for the Stack Exchange Network profile, like on all the other sites on the network? Or is the Stack Exchange account a generic one that can't be changed?
There are a few questions and answers about changing the display name but I don't think it addresses this particular question. Because the answers to those questions are usually about the synchronization mechanism.
For example, I saw this answer:
Did you change all of the display names manually, without using the synchronization mechanism? If so, try this:
- Go to your account page
- Click the "Accounts" tab
- Scroll to the very bottom
- Click the "Copy [site] profile to all Stack Exchange sites"
I have tried this, but in my case that option isn't showing up.