permutation

(noun) an event in which one thing is substituted for another. Synonyms: substitution, transposition, replacement, switch. Example: "The replacement of lost blood by a transfusion of donor blood."

(noun) the act of changing the arrangement of a given number of elements.

(noun) complete change in character or condition. Example: "The permutations...taking place in the physical world"- henry miller."

(noun) act of changing the lineal order of objects in a group.