Clip the 2nd button from the left on the top right corner of you sequence timeline. That's the link button. There are short cuts such as option key when selecting. Now you should be able to select the video or the audio and slide them independently. I'm assuming you want to slip the sync or continue audio/video intependent of the other.
You can also just delete the video from the sequence.
if you need to export just export to a sound only format.
