If memory servs me correctly - way back in 2009 or something I registered on this Forum. It's changed a few times (see the ReadOnly Old Forum section). I think I originally used the name 3Dprinter, but quickly decided to use me real name (well, the name every one calls me) - Msquare.
There was an option to set the name on the profile attribute page.
This has apprently been removed "recently" (I've not been on the Forum for a few months), and my old name has poped back up. Using google it still finds hits on Msquare, etc, but on the Forum all the generated listing and all use the 3dprinter name now.
Hrmph. Options
Learn to live with a bad choice made 10 years ago
Pester the forum people to restore the option to choose the display name.
Create a new account, being called a Newbie again...
Since the username "/dev" was taken, I registered as "-dev" and displayed it as "/dev". After the changeover, there is no such choice. And now other users (especially the newest) refer to me as "-dev". Not the same cachet.