OK, so if you take a look at our Themer’s Guide you will find instructions on overriding and customizing our templates. In this case, you are probably going to be interested in adapting the widgets/list-widget.php template.
The line responsible for generating the ‘schedule details’ is:
<?php echo tribe_events_event_schedule_details(); ?>
It’s output can be filtered; but since the same function is used from other templates it may be better in this case to simply remove it from widgets/list-widget.php and drop in a replacement function of your own.
Hope that helps!