Detaching audio from one clip:
Select clip (will be outlined in red and turn a darker blue)
Right click, Detatch Audio
Center clip audio is now detached on an Audio track (A1)
Playhead location 1:40 :
Left click on V1 (track header), Right click same spot, select Remove Track.
Export, using export preset: Audio / WAV
CRTL + Z (Undo) – this brings back the removed video track.
Right click on any track header : Add Audio Track (A2)
Import WAV file from where you saved it. Drag from Source to A2.
The extracted audio could be modified using Audacity or whatever other software you wish to use for audio editing. The reason why I didn’t move the A1’s clip to the left, thus removing any dead space before exporting to WAV is to make it easy for re-alignment once the clip is modified. You’re able to import the audio file, and it will perfectly aligned with your video like it once was.