We were installing fiber Nics and somebody tried to assign the management interface IP on one of the new ports. The result of course was an IP conflict and system went offline.

In the Linux world, you simply access the console, change a couple entries in files and reboot.

Such is not the case with Xenserver.  I tried to simply reassign the management interface, but it did not work. I decided to use the XE commands to remove the IP from the offending port (in this case it was xenbr1).

Locate the UUID by entering : xe pif-list

Drop the IP information by entering : xe pif-reconfigure-ip mode=none uuid=<big string>

One nice feature of Xenserver in this matter is you can tab out parameters and the UUID info after enter a few characters.

The system did need a reboot.