1) Changeability 2) Changeableness 
• (n.) The quality of being reversible.
in thermodynamics, a characteristic of certain processes (changes of a system from an initial state to a final state spontaneously or as a result of ... [3 related articles]
Re·vers`i·bil'i·ty noun The quality of being reversible. Tyndall. 
[n] - the quality of being reversible in either direction
noun the quality of being reversible in either direction
The ability to reverse actions mentally.