Activate last completed task in the flow

Hello Flowable community,

I am implementing decision tree, we have a lot of nodes, sequence flows and exclusive gateways. All nodes are user tasks. One of the requirements is to implement back button, and this for sure could be achieved with exclusive gateways, but I am wondering if there is more elegant way to do this? Is there possibility to go step back in the flow, delete current active task and activate last completed?