Me: I'd like to either change the username ([redacted]) on my account or delete my account completely. Can help me do that?
HN: Account renaming is something we plan to implement but haven't yet. You're welcome to email back in the future and check if it's done yet.
HN doesn't delete accounts. We do sometimes delete specific comments when users are worried about getting in trouble from them. Would that help?
I realize this isn't a very satisfying answer and am sorry.
Me: I didn't say anything nasty so I'm not too worried about it :) I'll just wait for the feature. Thanks.
7/26/2016
Me: Just want to check in and see if account deleting or username changing has been implemented.
HN: Not yet, sorry. There are some technical difficulties because YC uses HN IDs in its internal systems, which are separate, so we need to be extra careful not to make a breaking change. But we'll get there.
2/19/2017
Me: I need my account deleted immediately. It's a matter of national security, cannot explain in detail, orders from the President of the United States.
HN: That does sound urgent, so I'm sorry to have to reply this way, but we don't actually have the ability to do this. At some point we will have the ability to rename accounts to something anonymous, but unfortunately we don't have that yet either.
Me: Damn, now he's gonna make me go work on that wall :/
2/22/2018
Me: Are you able to change user names or delete accounts yet?
HN: Not yet, sorry, but it is coming. Do you want to be on an email list to get notified when it's ready?
Me: Yes, that would be cool, please add me.
HN: Ok, you're added.