We give a systematic method to determine the asymptotic flatness preserving transformations in the three-dimensional SL(4,R)/SO(2, 2) sigma-model arising from a five-dimensional gravity coupled to a dilaton and a three-form field. The permitted transformations depend on the coordinate choices. By focusing on three cases, namely the Kaluza-Klein black hole, five-dimensional black hole and black ring, we find out all possible asymptotic flatness preserving transformations and apply them to generate charge from single rotating vacuum solutions.