2 locations, one no longer with wi-fi

We've moved. Leaving existing Ring equipment for New Owner, with Closing next month. Cancelled internet service in old place when we moved out. Want to delete Location (Old, and Professional Monitored), and ready to establish New Location and change to Pro Monitoring. But without Wi-Fi at Old location, stymied to delete all devices so that I can cancel Old Location. Frustrated. Can someone explain the process in a simple way (this can't be a unique situation)??