So this is the first time seeing a guest review come through since converting my OwnerRez to API connection. I want to add a short reply to the review as the owner but cannot find anywhere to do that through OwnerRez. Am I correct in that my response can only be done directly on Airbnb? This was from a reservation long before I did the API connection if that makes a difference. Thanks.
You should still be able to write the response in OwnerRez and it'll be transmitted to Airbnb via the API, because the Airbnb API generally connects even bookings created before you established it:
https://www.ownerrez.com/support/articles/respond-to-reviews#respond
However, if you like, you can write in to the Helpdesk with the booking number, and we can investigate if it doesn't seem to be working as expected for you.