The general idea is that they have a process instance which gets aborted (accidentally) in the middle of it, so they want to restart it and jump in the original state, i.e. activate those nodes which were active before abort. So they would like to specify explicitly from which node it should be started. For instance, imagine the following process definition "start -> ht1 -> ht2 -> end" and we need to start it from HT2, skipping HT1 all together.