Sign in to a different primary iCloud Account
This is driving me nuts. I have a MacBook Pro that is signed in to iCloud with account xxx. I have a Mac Mini that Is signed in with iCloud account YYY. Yes, I screwed up when I built the mini - I should have used xxx, but that was my bad. So, because they have different iCloud settings, I cannot share my Pages documents between them. I want the Mac Mini to also sign in to iCloud with account xxx. Both are running current incarnations of Catalina.
I have done a bazillion Google searches on how to sign out of a primary iCloud account and back in with another, but it simply does not work on my mini. I click on the Apple logo at the upper left corner and go to System Preferences.... then the Apple ID icon at the top right corner. There I click on Overview, and Sign Out. It asks if I want to keep a copy of my iCloud data for Contacts and Calendars. I click on Keep a Copy, and then it just gives me a list of all the apps using iCloud on that machine. It still shows me as being signed with the yyy account. Nowhere does it show me a place where I can log in with the xxx account.
What am I doing wrong here?
Mac mini, macOS 10.15