  Let G be a locally compact group, H an abelian subgroup and let f be a
continuous 2-cocycle on the dual group of H. Let B be a C*-algebra equipped
with a continuous right coaction of G. Using Rieffel deformation, we can
construct a quantum group G(f) and the deformed C*-algebra B(f). The aim of
this paper is to show that B(f) is equipped with a continuous coaction of G(f).
The transition from the original coaction to its deformed counterpart is
nontrivial in the sense that the deformed one contains complete information
about the undeformed one. In order to illustrate our construction we apply it
to the action of the Lorentz group on the Minkowski space obtaining a
C*-algebraic quantum Minkowski space.
