Deleting Operations/Sub-Operations 
The system deletes the operations or sub-operations.

If you delete an operation in a maintenance task list for planned maintenance which is in operation in your company, the maintenance items that were already released at the time the task list was changed will still contain the operation that no longer exists in the task list.
If a released order refers to the task list in which you deleted an operation after the order was released, the maintenance order also contains an operation which no longer exists in the task list.