A blind change is a move that gymnasts must master on the uneven bars.  This video shows the action and gives you a close up view so that you can get an understanding of what the hands and arms must do in order that this move is done correctly.



USgyms.net describes a blind change in this way:

A move used to get from regular grip to L-grip. From handstand, the gymnast rotates outwards (so she is facing away from the bar) on one arm to do a ½ turn, ending up in L-grip.

Read more at http://www.usgyms.net/bars_skills.htm

Gymnastics Zone describes it in this way:

A high bar or uneven bar skill done from a back giant, with an inward pirouette (on post arm, ½ turn inward toward stomach) over the top of the bar to end in a front giant. Blind changes are used to transition from back giants to front giants or you can do a blind change and an additional 1/2 pirouette into another back giant.

Read more at http://gymnasticszone.com/definition-blind-change