Update child device settings from service manager

Does anybody know how to update the settings of a child device from the service manager? I can create a device from the service manager, but I want to update the settings for the device:

preferences {
    input "apiKey", "text", title: "API Key", required: true
    input "iden", "text", title: "Device Id (leave empty to push to all device)", required: false
}

Nobody has any ideas?

Did you ever solve this issue?