how to put center channel voices in rear speakers

I enjoy hearing the dialog in the rear speakers as well as
in the center. Is there a receiver that has a setting that will do this? or do I have to splice my center channel wire
to output to the center and rears?

I have a 5.1 setup
Denon 2803
Ref 3.1 fronts
orb audio mod4 center
orb audio mod2 rears

thx
scott