I bought a 21 inch front wheel used with the single matching rotor, I would like to switch it back to dual rotor setup instead of switching everything over to make single work

 

Buy a wheel for dual rotors? Leave your existing wheel on and forget it? Really not sure what you would like to know,more info and pics needed.

 

Is there a way to add the second rotor to the wheel, thought it was clear, the opposite side of single rotor is smooth chrome. Is my only option to go and switch legs, get 6 piston caliper.