A conductor leading a band in music.
A conductor stands in front of the band.
Leading a band in music can only be done when one stands in front of the band.  One can hardly lead a band sitting.
exists e1 x1 x2 x3 x4.(a_topic(x1) & in(e1,x4) & n_music(x4) & Theme(e1,x3) & Actor(e1,x2) & v_lead(e1) & n_band(x3) & (x1 = x2) & n_conductor(x1))
exists e1 x1 x2 x3.(n_band(x3) & in(e1,x2) & of(x2,x3) & n_front(x2) & Actor(e1,x1) & v_stand(e1) & n_conductor(x1))