Cox is on a 24 hr DHCP, so depending on when the modem updated the IP address, he's got 24 hrs from that point. Leaving it unplugged for 24½ hrs will only work if someone new comes online and their modem requests an IP address and HIS address is handed over. Works sometimes, most of the time, not. Deprovision/reprovision won't work, what MIGHT work, is for them to put his modem in what is called, "AUP". AUP is a form of suspension used for copyright complaints, and soft disconnects. It will put the modem in a 172 non routable IP address, and it sets the IP address back ont he DHCP server as available, and then when they put the modem back in the system, online and AUP removed, it will be handed the NEXT available IP address which should be different then the one they had.