I have a few devices running and resolving with a fix IP address and sending syslog to NETXMS server.  These devices are mostly routers.  My question is when I change the router device IP, the device seems to continue to work fine and DNS is updated. But all the syslog messages are no longer updating.  I cannot seem to get them back.  Is there a way to remap the old device ip to new one.

I've tried deleting the device, and readding it back, but nothing seems to make syslog update the new address to allow the messages to map to the device. 



Thanks

Make sure that IP address in node's Properties -> Communications is correct.
Then run Configuration Poll on that node.

If it's still not working, try enabling debug, from Tools -> Server Console:

debug syslog 6

and check server log lines when your device sends something.