1) Alternation 2) Commutability 3) Convertibility 4) Fungibility 5) Inconvertibility 6) Interchangeability 7) Interchangeableness 8) Permutability 9) Permutableness 10) Replaceability 11) Substitutability 12) Transferability 13) Transposability 
• (n.) The quality or state of being exchangeable.
Ex·change`a·bil'i·ty noun The quality or state of being exchangeable. « The law ought not be contravened by an express article admitting the exchangeability of such persons.» Washington. 
[n] - the quality of being capable of exchange or interchange
interchangeability noun the quality of being capable of exchange or interchange