change state, turn - undergo a transformation or a change of position or action; "We turned from Socialism to Capitalism"; "The people turned against the President when he stole the election"

stiffen - make stiff or stiffer; "Stiffen the cream by adding gelatine"

alter, change, modify - cause to change; make different; cause a transformation; "The advent of the automobile may have altered the growth pattern of the city"; "The discussion has changed my thinking about the issue"