Returnable and Commutable

adjective

• That may be returned.
  • usage: "returnable bottles and cans"; "this merchandise is returnable if you save the receipt"

• (a.) Capable of or admitting of, being returned.
• (a.) Legally required to be returned, delivered, given or rendered; as, a writ or precept returnable at a certain day; a verdict returnable to the court.

adjective

• Subject to alteration or change.
  • usage: "the death sentence was commutable to life imprisonment"
• Capable of being exchanged for another or for something else that is equivalent.
  • synonyms: substitutable