no lah...if just to change steps if the person wrong
steps,
dun need command, just either skip a step or have a smaller step
then join back with the correct foot on the next step.
Else if you want the WHOLE contingent to change steps, command is
some thing about "TUKAR LANGAR......"
command will end at left feet, and they will "check bang" and
restart marching in quick time.. 