How do I restore an old identity and switch to it?

Split from this thread.

I realize this is an outdated post, but could not find anything more recent. I am on Yosemite. Trying to retrieve a "conversation" of inbox emails that was accidentally deleted one month prior.

I backed up my main identity, then restored main identity from Time Machine. It restored directly to the Main Identity folder, no option to restore to desktop (that I could see). Since you can't "switch" identities anymore, I closed Outlook and reopened with the restored identity.

No missing emails appeared. No change at all that I can see.