If you have an Edge SDK application or EMS on your Pi, then you just need a property defined on the Pi that is defined with ReadOnly=false and a push type of Always or VALUE. Once you have that set up and the application on the Pi is connected to the ThingWorx server, just update the property on the ThingWorx server.
The update will be sent to the Pi, and then sent back to the platform. You may well find that the value doesn't update on the platform until the remote device has processed it.
