Some background
I just received my EdgeRouter X. I updated to EdgeMAX v1.9.0 immediately, and then set up the ER X to be my new router using the Basic Setup wizard that turns eth0 into the WAN port, and eth1-eth4 into switched ports. The ER X's IP is 192.168.1.1 (the default). My previous router was configured - for reasons that are no longer relevant - with an IP address of 192.168.1.2.
I have two unmanaged, 8-port switches attached to eth1 and eth2 on the ER X. All of the network's remaining connections are plugged into these two switches and not into the ER X, i.e. ER X ports eth3 and eth4 are not in use.
Problem
I have a computer attached to one of my switches that is only accessible to me via the network. I do not have access to a keyboard & monitor to administer the computer locally. This computer was configured to use the old gateway (192.168.1.2), and now it is not retrieving an IP address from the DHCP server on my ER X. Laugh if you want to, but this is the current predicament. 
Question
Is there any way for me to regain access to the inaccessible computer by configuring the ER X to serve up DHCP-assigned IP addresses from both 192.168.1.1 and 192.168.1.2?
Extra info
1) The inaccessible computer has a web portal that I can access via a web browser if it had an IP address.
2) I could also ssh into the inaccessible computer if it has an IP visible to machines on my 192.168.1.x network.
3) I don't know enough about networking to understand if a DHCP client assigned from one gateway is visible to DHCP clients assigned from another gateway.
4) I'm certain that if I gain access to the computer I can change the default gateway from 192.168.1.2 to the new ER X's 192.168.1.1. This is what I plan to do as a permanent solution if I gain access to the computer.
If the only solution is to gain local terminal access to the computer, I'd like to know that. This ER X is so fancy, though, that I'm betting there is a way to solve my problem without local terminal access. I suppose another solution would be to put the old router back in place, gain access, change default gateways, and reconnect the ER X. I'd like to avoid doing that, too.
