Binance referral discount on trading fee after sign up

I signed up for an account and have been trading regularly. Only after the fact did I realize that I can reduce the amount of fees I pay per trade by using a referral code to sign up.

Is there anyway to get a fee reduction now that I have already signed up?

If I refer someone perhaps? Or would I have to make a new account? Or can I refer myself a sub-account? The detailed rules are not clear to me: https://www.binance.com/en/support/faq/cbac15853b0243cda4a90c9c03ca0c38

Thank you