Pace 5286AC Firewall settings

We recently had our ATT gateway updated to the Pace 5286AC.

When the technician came out to set up the new gateway, he modified the firewall
settings of Applications and pinholes to allow his iphone through the firewall.

I want to remove his phone but I cannot find out how to remove a device from the list. When I go to the settings tab after connecting to the gateway/router

I click on the Firewall section then the Applications, Pinholes and DMZ area under Firewall you see item 1) Select a computer - indicates you choose a computer that will host applications through the firewall;

The list of devices shown on my list has his phone as the selected device allowed
through the firewall but there is no way to remove that previous selected device.

I read through the firewall section of the Pace manual but they do not cover that topic of removing a selected device.

Anyone discover how to do this yet? Thanks in advance.