If you want to edit or remove a highlight video which you have created, you can do this through your Dashboard.
First, go to your Dashboard.
Then, select the show from the dropdown menu which corresponds to the show from which the highlight video was made. Once you've confirmed that the selected highlight video is the one that you want to remove, click "Edit or remove your video".
This will take you to the interface to edit or remove your highlight video. If you want to change the portion of the show which is used as the highlight video, you can do it from this screen. To remove the highlight video, click "Unpublish your video".
This will remove the highlight video from your channel, and will also remove the highlight video from Concert Window's YouTube channel.