I need to send a copy of an efin acceptance letter RECEIVED BY MAIL from IRS. What address/email address should that be mailed to?

(In order to change credentials from CPA to EA, or to change address for same old account at intuit, consequently for same old efin and same old PTIN)

(Only option online(period!) is to send e-fin application summary page from the eservices account at IRS and that doesn't work for me.