change Outlook (new) "Office Account"?

How do we change/login to another "Office Account" in the new Outlook?

In old Outlook desktop app for years now, we can go to File/Office Account to log into our work/school accout which is subscribed to Microsoft 365. BUT, I don't see where to do this in the Outlook (new), which is only using my Windows PC login, which is personal, and doesn't have a subscription. 

Why: the ads are very annoying. And maybe we're missing other features w/o access to out subscription account?