How to undo the Auto-Sync operation

The Auto Sync function is great, but how to undo this operation. Let's say if I did Auto-sync Video and Audio in media pool using "based on waveform". Then append it to timeline and edited it. After I decided to bring back original audio from video. Every time from now on when I pool that video to timeline it uses only synced Audio, but original disappears unless I import that video again in media pool, which is lot's of a mess. Please, help. Check lots of articles, seems like everyone can Auto Sync, but no one knows how to undo this operation. Thank you!