I want to reconnect to Github with another account, but failed. Any attempt to reconnect by Https not removed SSH authentication.

But

ssh -T [email protected]

still show my old name.

I working from Linux machine.
My ~/gitconfig is empty, ~/ssh of course not empty. I have rsa keys, certificates and this config – all this key bind to new account

 Host github
    HostName github.com
    IdentityFile ~/.ssh/id_rsa
    IdentitiesOnly yes 
    AddKeysToAgent yes

But Github still don’t allow change me my old name in SSH command.
What I need to do to force Github accept my new name in SSH?