My question is, why does the forum not have a feature that can allow members to reset their username easily, when ever they want.
It would create a mess if that was easily available, and it would be perfect situation for scammers and cheaters in forum.
Note that members can change usernames with approval of admins, mostly for privacy reasons, but unique profile ID number will remain the same.
Not only the ID but the old username also remains, as only the display name is changed meaning you can only log in the forum with the old username and not with the new display name if I'm not wrong.