title: How to do a transaction rollback in corda
body: <p>How can I do a transaction rollback in corda. Let's say I've a complex flow which includes 2 flows. I want to rollback the previous transaction if the last one failed how can I do that in corda? Or I need to re-design my complex flow or invalidate the previous state created myself? eg: I've a main flow.in that I created subflow which creates a new state (or updates some state). now suppose for some reason the main flow fails how do I rollback transaction created by my previous subflow?</p>