Workaround:1. In the Service Editor, choose to create a SD file of the service you wish to overwrite. If you already have a feature layer with the same name, it will alert you and not go any further.2. Give the SD file a slightly different name. This is to get the Service Editor to actually create the file.3. After the file is created, rename it to match the existing SD file's name.4. In AGOL, you will need to delete the feature layer associated with the SD (this is to give you the option to update the SD). Once complete, go to the item details of the SD, and choose to update. Use the SD file you created, and it should successfully update.5. Once complete, choose to publish the service from the SD item details page, and it will create a new version of the feature layer.- Alternately, you can delete the feature layer (not the SD) before you choose to overwrite, and it shouldn't stop you from naming the SD file with the same name as the existing file. This might be a slightly smoother approach, compared to the above.(these approaches were functional as of 11/1/2016)