Is it possible to request username and account number to be changed?

I have an account from 2011 that unfortunately has a reused username and links to my address that can be traced to my holdings today.

I want to keep the account as it is so old but am hoping I can get the username and account number changed.

It cannot just be a username change as there are lists of username linked to account number out there:

https://github.com/dirtyfilthy/bitten/blob/master/utils/addresses.txt