If a sub flow chart is orphaned (it ran asynchronously and the parent flow chart completed before the sub flow chart), it can be difficult to remove the sub flow chart from the engine. This can cause problems if the sub flow chart enters the FAILED state, since flow charts in that state must be manually recovered or removed, but the remove operation cannot be performed directory on a sub flow chart.
Instead, you must call the remove operation on the parent flow chart's namespace, adding a wildcard ('*') character to the argument so the sub flow chart is picked up correctly.
For example, if you had a sub flow chart action on a flow chart named "/MyParent", you could call the following code to remove the sub flow chart:
Keep in mind that this will remove all sub flow charts that were running under the specified parent. There is no way to remove only a single sub flow chart from a particular parent.