needing help deleting old accounts

So I've discovered I cannot delete my own accounts. If you can well then I'm blind because I did not find how.
The account that I'm posting this threat on I wish to keep.

I have a four old accounts that I don't use anymore since I don't like their usernames. Some of the accounts haven't even been used that much but I want to delete them now.
Is there any way that I can delete them or get someone else to delete them? Do I have to contact someone specifically?

 

I'd try asking Myz or Rika in DM

 

thank you