Is there a way to manually reassign a device from the xFi pod it has automatically selected to a different pod?
No. Once devices join your home WiFi network, they will automatically connect to the best WiFi access point, whether that is your Gateway or Pods.
In a WiFi mesh network, the best connection point for a device may not always be the one that's closest to it. Pods communicate with each other and the Gateway to monitor the number of devices connected in the home, their location, and the type of WiFi connection that each device needs. This ensures that your device is operating with the best signal.