Demonstration
View the clip:

Nathan is taking the role of the lead on the left, Shirin the follower is on the right. Shirin is simply performing the lower body action using alternating legs. Nathan is also performing the action but he occasionally taps his foot instead of stepping, causing a change in phase. You can observe the phase changes by watching the tilt of their hip-lines. If the changes occur too quickly, pause the clip and use the slider to control the images frame–by–frame.

Preparation
You must be competent with the content of the Lower Body Action tutorial. We also need to have a couple of definitions:

1. A step is a foot placement followed by a weight transfer;
2. A tap is a foot placement without a weight transfer.

All exercises are to be performed on the spot.
 

Description (Part I): a Step, a Tap, and the Difference

Stepping
If you perform Stages 1 through 7 described in the Lower Body Action tutorial, you would have taken a step (placement + transfer).

Tapping
If you perform Stages 1 through 3 described in the Lower Body Action tutorial, you could have tapped your foot (placement only).

The Difference
Is in the weight transfer. By transferring your body-weight completely onto a foot placement, you will not be able to move that leg and have no alternative but to use the other foot next. If you don't transfer any weight onto a foot placement, you will be free to use the same foot again.

In terms of pressure on the sole of you foot, a step is felt as sustained greater pressure, whereas a tap is felt as a brief lighter pressure.
 

Description (Part II): Changing between Steps and Taps

Verbal Cues:
Step–Tap–Step–Tap
or
One–Two–Three–Four

Prepare to start:
Stand with your weight on your left leg ready to move onto your right.

Beat:

1.	Step onto your right leg.
2.	Tap with your left leg.
3.	Step onto your left leg.
4.	Tap with your right leg.

Your weight should now have returned to your left leg, and be ready to move onto your right.

Repeat the sequence.

Practice with the first verbal cue until you're fluent, then try it to a count (second cue).
 

Description (Part III): Changing phase within a music framework
(The phase change in this exercise occurs at the end of a bar of music)

Verbal Cues:
Step–Step–Step–Tap
or
One–Two–Three–Four or One–Two–Three–Tap

Prepare to start:
Stand with your weight on your left leg ready to move onto your right.

Beat:

1.	Step onto your right leg.
2.	Step with your left leg.
3.	Step onto your right leg.
4.	Tap with your left leg.

Notice that at the end of beat four, you should be ready to use your left leg. This means that if you used a single phase change in one bar of music, you would start the next bar with a different leg (in this case, with your left leg instead of your right; you will continue to start every bar stepping onto your left leg until you change phase again).

You should also practice the exercise stepping onto your left leg on beat one.

Once you can do that, you can perform the sequence continuously.

Practice with the first verbal cue until you're fluent, then to a count (second cue).
 

Principles
A tap is the most simple method of marking time, which is a fundamental concept in dance. The period of inactivity that this generates whilst keeping track of tempo, allows sequences of steps to be broken up or rearranged to suit a dancer's choreography.

Goals
By the end of this tutorial, you should be able to perform the phase changes smoothly, as demonstrated by Nathan in the video clip.