Training Plan-Delete

If you want to delete workouts from your Planned Training Log, your best bet is to use the Bulk Modification Tool.  Just be sure that you're in your Planned Training and not your Actual Training.  As long as you do that, all of the data you've recorded is safe.

To change the plan that's listed at the top of your training log as your current training plan, that's done from the Defaults tab of your Training Log settings.