I don't think Staff will delete your account, as in, scrubbing your data from their server. You could change your username, avatar, email, password and other account details to anonymize your account in a way. But your posts will remain public along with all the metadata unless you ask a moderator to remove them, in which case it's still on their server, just not visible/public anymore (called soft delete).
One way to leave this forum is to schedule final goodbye thread on a future date, which is what
@hewiof did [
link]. If you hover over her name then you'll see there's no option to start a chat or conversation, which probably means that she got banned* when a moderator saw her scheduled thread posted.
If I come at the deathly crossroad then I'll likely want my account to be left accessible. I have a password safe that holds the login credentials to all the accounts I ever creating which I'd like to give to my family.
* Edit: there are also users with crossed out names. I don't know the difference.