Let X,Y be a smooth projective varieties, say over the complex numbers, both acted upon by a connected linear group G. Let f:X-->Y be an equivariant rational map. Let Z be a smooth G-subvariety sitting in the indeterminacy locus of f. Let X' be the blowup of Z in X. Wish a reference to show (1) the action of G extends to X', and (2) the rational map f:X'-->Y induced by f is equivariant.