The command is CHANGE STEP, MARCH. It may be given while marching at quick or double time, marking time, or double-timing in place.
The command of execution is given as the right foot strikes the deck.
While marching at quick time or double time:
On MARCH, take one more step, 30 or 36 inches, as appropriate.
As your right foot comes forward to the next step, place the toe near the left heel and step out again with the left foot. This changes the cadence count, but not the rhythm.
While marking quick time:
On MARCH, lift and lower the left foot twice in succession.
The second time it touches the deck, raise the right foot and continue marking time.
While double timing in place:
On MARCH, hop twice on the left foot.
Continue double timing in place.