How to Change Local IP Network Address Scheme

We have a Technicolor CGA4131COM. 

In the IPv4 section, The Local IP Network is set to 10.1.10.1. Our current wired network infrastructure is all provisioned with a 192.168.2.x address structure. My goal is to change the DHCP IP address to match our existing downstream devices. We have a bunch of NDI cameras, switchers, etc and I'd rather not have to go through and change all the device IPs 

I can enter a new "gateway address to 192.168.2.1, and the DHCP beginning and ending address refresh properly onscreen. When I click on Save Settings and confirm the reboot after a while the page refreshes and the IP address hasn't changed.

What's the magic trick?