If you have an ArcGIS resource (MapServer) and want to pull a layer from it to upload to Social Pinpoint, you can use a neat Python commandline tool
Once installed you can issue a command such as
arcgis-get https://<URL OF SERVER>/MapServer 0 > yourfile.geojson
The number after the URL is the LayerId
ℹ️ The geojson can then be uploaded to Social Pinpoint.