Is it possible to delete an account?

Hello.

Maybe a weird question; but as the title suggests, would it be possible to delete an account I have [namely the one used right now to post]?

Quite simply, I'd prefer to change my account username, while maintaining my forum nickname. At first, I thought it would be possible to just change the forum nickname of this account and create a new account with the old nickname. Still, that doesn't seem possible from what I've seen in the settings screens.

Any help would be appreciated. Thanks in advance.