Scroll down to the Licenses card on the right.
Hover over the license you want to delete. Click on the Edit (pen) button to the right and a form will slide out from the right.
A form will slide out from the right, at the very bottom of the form, click on 'Delete License'
To cancel any changes you've made, simply click the left arrow in the top bar. You will be prompted "You have unsaved changes. Are you sure you want to leave without saving?" Just click 'OK' and your changes will not save.