I had Office 365 installed manually from Microsoft using their installer. I didn't even have to uninstall it, just downloaded from the App Store and it updated

I had Office 365 installed manually from Microsoft using their installer. I didn't even have to uninstall it, just downloaded from the App Store and it updated to that installation option now. I didn't have to log back in, or do anything other than enter my keychain password (many times) for it.