At any one time, a kit can only have one active configuration (or none!). The moment a configuration is activated, it can no longer be changed. This ensures that data and measurements produced can always be traced back to the exact configuration that produced it. To change a configuration, it has to be copied, and that copy can be changed and then activated. There's not yet a user-friendly way to copy configurations, and you'll have to do it manually. Solving this is high on our priority list.