How to get vocals out of a 5.1 Audio source

Hello! Recently I downloaded a t.v series that had a 5.1 Audio source and whenever I play it through the waveform the vocals are always taken out how ever. When I export the Audio it exports it through the multitrack which then the vocals are still in the audio. I'm trying to sample a song so is there any way I could get the best audio with no vocals without  having to try and duplicate the audio in multitrack. I am currently using Audition CC 2018 thanks! ~Anthony