Scholaric Users can delete a series of lessons.
When you delete a lesson that is part of a series, you will see a new checkbox in the delete dialog:
If you select delete series, then all lessons created as part of that series, from that date forward will be deleted as once. This also gives you the ability to redo a series, and change the schedule or text, or whatever you want.
This applies to all repeating lessons created in the last week, since I've started tracking them this way.
My apologies for not going back further on this, but Scholaric is approaching a quarter million lessons, and I would have to take it down for hours to retrofit them.