First, have the figure posed that you want to reverse.
Select the figure in the Scene Tab.
Click on the 'Active Tab' options button on the Parameters Tab. This button is in the upper right corner of the tab.
In the menu that appears, choose “Symmetry.”
In the Symmetry Dialogue Menu, choose the following settings:
Direction: Swap Left and Right
Trunk Nodes: Leave Alone
Left Node: left;l
Right Node: right;r
Transforms: Rotation: check x, y, z
Translation: Check x, y, z
Scale: all unchecked
Press 'Accept' on the bottom