You can unapply a Training Plan from an athlete or un-share it from another coach by clicking on that plan in your plan library and then clicking the gear icon in the pop-out window. If you already have the plan loaded to the calendar view you can also click on the title of the Training Plan to open the settings.
1. Click on the training plan and then the gear icon to access the settings of this plan.
2. In the settings window that opens, click 'Manage Plan' on the left. You can then further select 'Applied To' or 'Shared To.'