Cambia direccion means change direction. In the rueda the dancers makes a turn and dance the other way (man goes arriba, ladies abajo).
In the ábaco figure we make a parada, doing a step without shifting the weight. When we continue we are now on the men’s fottwork, stepping on left foot on 8.
If cambia direccion is called again, in ábaco we repeat the parada, now with the left foot. Afterwards we are back on the original contratiempo steps, stepping on right foot on 8.
It is common to end Tumba Francesa after one cambia direccion with an enchufla figure.
To exit you need to step on 8 with your left foot to get into enchufla on right foot on 1.