In this paper we study the β-change of Rizza manifold associated with the generalized Finsler metric. It is proved that Randers change preserves the C-reducibility. We consider the Randers-change (superscript *)L=L+β and proved the conditions for Rizza manifold to be C-reducible, Berwald and Landsbergian. Also we obtain condition for Rizza manifold to be C-conformal to a locally Minkowski space.