How to resolve a network setting lock out

I locked myself out of my XServe running Mac OS X Server 10.4.9 while trying to turn on Ethernet Link Aggregation. I am not physically close to the machine. What options do I have to get onto the machine and reset the network settings? Can it be rebooted with it's TCP/IP settings set to DHCP? I can get on a machine on the same network but I can't even see it with arp. I've had it rebooted but that didn't help. I even rebooted my cisco switch in case it got jammed with the change in "hardware" configuration when I clicked on "Apply" after configuring the link aggregation. Any ideas? Thanks, yon.