Animation: Root of armature Picture a monkey climbinga a hanging wire, hand over hand, then take away the body, so only arms, the bone structure goes from on hand to the other. 
The root of the armature will be in one of the hands. 
It is easy to animate the first "hand over hand" motion, but when the "Root" hand need to move over the "free" hand/bone then I am struggeling. 
Is there a way to do so without messing up the motion?
After a couple of frustrating ideas, I finally made it work.

I parented the objects to two armatures.

The first is Head up, and the second is Head down.

After animate the armatures, I swapped the visibility influence of the armatures in the Modifier Tab storing as keyframes.

I sent my file for analysis. Version 2.79b.


See the images below.