Another approach within VP is to split out the audio track areas where audio should be lowered.
Then double-click each of those split-out audio clips. The audio waveform appears in the preview window with that clip highlighted.
'Grab' the line and pull it down to the level desired for each clip.
Or split out audio track areas where gain is to be reduced, then select all those clips.
Click fx on one of them and choose AMPLIFY. Set gain to - say 85% - and click the fourth button from the left in the toolbar, "Replace effects chain.."
That should apply the reduced gain to all selected audio clips.