How to log into an old Apple ID?
I have two different Apple IDs, each linked to a different email address. The old one I had forgotten about, and when I got a new Mac must have started a new one.
The App Store application automatically logs me into my new account, and I see no way to change that address and log into the old one so I can look at the purchases there. I've tried going through apple.com, (the old way), but it just opens up the App Store.
Outside of having to change my entire iCloud settings--sounds very risky!--how can I get to the old account? And, is there a way to merge two Apple IDs?
MacBook Pro 15″, macOS 10.14