OK, AFAIK there's no process on the NBA.com site to request a position change so here's the process:
Come to this forum and post a vote thread such as,
"Should Shaquille O'Neal be listed as a Guard instead of a Center."
Have 2 poll options - yes and no.
Make it a public poll just in case an ABA member sees it and votes by mistake. Set it to close after 24 hours.
I'll use the same voting process as sports.ws to determine the result - over 50% voting yes with a minimum of 7 yes votes and I'll manually change the player's position.
The key here is to make sure you have your justification fleshed out before you post the poll. You could change your vote on sports.ws - you can't do that here.
I've now updated all Keepers to where they were at the end of last season. Feel free to start putting players up for votes any time.