Something very simple and can be done in seconds if you know where it is location.

1. Right click on the video clips timeline then select Speed Duration from the menu list.2. Check the box Reverse Speed from the popup menu and then click on OK.

1. Go to the sound channel in the timeline of your movie clip and right click. Look for Unlink from the menu. (This separate the video clip from the sound allowing you to delete it.)2. Deselect everything by click on an empty area in the timeline. Then select the audio you would like to remove. Press backspace or delete on the keyboard.