Headless Xserve G5, no video card, need to change IP address, can’t access

A client messed around with the server IP themselves, screwed it up, now it cannot be accessed via ARD on the network. This XServe has no video card so we can just hook a keyboard and monitor up to it I need to know, is there any "hard reset" that will set the Ethernet ports back to default DHCP settings, just so this machine will pick up a valid IP from the router and we can access it again to change settings? Looking forward to a response from a [b]real[/b] Mac Genius