How do you reset default app for opening files in Onedrive?

[Android Central Question]

I recently made the classic error of accidentally clicking 'always' instead of 'just once' for the default app to open files in Onedrive. I've tried resetting ALL defaults (didn't work) and, bizarrely, the Onedrive reader does not appear in list of individual apps. I assume it is somehow connected to the main Onedrive app but this has has no default settings attached.

Can anybody advise? This is quite annoying because the Onedrive reader has limited functionality compared with other PDF readers, plus it opens Word docs too which I'd really rather open in Word.

Using Samsung Galaxy Tab A (2016) Android version 8.1.0