Your User ID cannot simply be changed to another name (either by you or by us as administrators). You would essentially need to create a new User ID and start posting under a new ID. Unless your old User ID was deleted (we can do that, you do not have the authority to do that yourself), you would also need to attach a different email address to the new User ID to be able to activate the new ID.
We can delete the old/current ID for you so that you can register a new ID and associate it with the same email account (if you wish to keep the association with the same email account--though if that reveals your true identity, probably best to change it, too).
Having said all that, that's only going to protect your real identify going forward. Deleting all your previous postings would be the only way to effectively expunge any evidence of Jamie Bowman ever having posted on this bulletin board (there is no way, using this software, to simply change all your previous posts to posts having been authored by a different User ID--it's an all-or-nothing kind of proposition--either you're comfortable with old Jamie Bowman posts outstanding or, to remove that user ID, you've got delete all the old postings altogether).
In short, we'd be happy to help and happy to explain the various options/results available. For some of them, however, you're going to need our help to implement.
Please email me privately to discuss further. We certainly want to you to end up with a result with which you're comfortable.