About Returning Comcast Modem Router

Hi,

Recently I have started to receive internet service from Xfinity including a modem router. Now, I have my own router and I want to return Xfinity modem router to an Xfinity Store. 

Do I have to return all wires with the modem touter too? Wares: Power cable, coax cable and internet cable.

Thanks in advance,

Akdogan