[Tango-L] "changes of direction"

[Chris, UK]

Can someone explain to me what a tango scientist means by "change of 
direction"? As here, for example:

 Level 3+ (elementary and better) means -you are confident with the basic
 steps (side, backwards & forwards), you can pivot confidently and have
 some experience with the cross, ochos and changes of direction; 

"side, backwards & forwards" is change of direction of travel, and "pivot" 
is change of direction of facing, so what other change of direction is 
there?

--
Chris