In this paper, we investigate the change of Finslr metrics $$L(x,y) longrightarrowoverline{L}(x,y) = f(e^{sigma(x)}L(x,y),beta(x,y)),$$ which we refer to as a generalized $beta$-conformal change. Under this change, we study some special Finsler spaces, namely, quasi C-reducible, semi C-reducible, C-reducible, $C_2$-like, $S_3$-like and $S_4$-like Finsler spaces. We obtain some characterizations of the energy $beta$-change, the Randers change and the Kropina change. We also obtain the transformation of the T-tensor under this change and study some interesting special cases. We then impose a certain condition on the generalized $beta$-conformal change, which we call the b-condition, and investigate the geometric consequences of such a condition. Finally, we give the conditions under which a generalized $beta$-conformal change is projective and generalize some known results in the literature.