Unhandled Exception
One of the most common use cases for resubmission is when a step in a process fails and there is no exception handler for that step, referred to as an unhandled exception. If an unhandled exception occurs, both the step and process instance are marked as "Failed" in Monitor and the pipeline for the failed step is saved at the point of failure.
The process instance continues to execute if there other tracks in the process that were executing prior to the failure, until the instance reaches a logical stopping point.
You can then locate the failed instance and step, edit the pipeline, and resubmit the failed step. The process instance will then continue executing from the point of the unhandled exception to its logical conclusion using the modified pipeline values.