You can use the <node3D>.parent command to do this:
Code:
import viz
viz.go()
gallery = viz.add('gallery.ive')
court = viz.add('court.ive',scene=2)
avatar = viz.add('vcc_male.cfg',pos=[0,0,2],euler = [180,0,0])
avatar.state(1)
#switch between scenes 1 and 2
vizact.onkeydown('1',viz.scene,1)
vizact.onkeydown('2',viz.scene,2)
#move the avatar to scene 2
vizact.onkeydown(' ',avatar.parent,viz.WORLD,scene=2)