You can simply remove the Multi Device SIM from your additional device and insert it into your new additional device. If the SIM is too big for your new additional device, you can order a replacement SIM in My Swisscom Business (Customer Centre) or – for the opposite scenario – use a SIM adapter.
If you want to switch from a device with an eSIM to an additional device with a SIM, you need a Multi Device SIM for your new device. In the Cockpit, select the device you want to exchange and click on “Exchange device”. You will then be prompted to activate the new SIM.