As input I have a csv file. The column names are dates. I use python to download it from an ftp and then merge with a spatial dataset to create polygons.
I usually update an AGOL service but I don't know how to update an AGOL service if my column names (attributes) are changing daily. This would require to delete and republish, but FME cannot publish a service, can just do an update. Any help is greatly appreciated!

I don't think FME can delete a feature service, or remove a layer in an existing feature service. So you might have to use the HTTPCaller to call the