To delete Sessions and Presentations we have many ways to achieve it, starting with 5.17 Sessions and Presentations:
With this view, you are able to delete the sessions and also the presentations, it can be done individually by using the delete icons next to every session and its presentations:
Note that if you delete a session that has presentations, it will delete all its presentations as well.
And finally, we are going to be able to delete in bulk by using the buttons at the top of the view when selecting rows:
Also if you would be interested the following articles may help: