c7000v2 setting the time zone

> [...] I'm on firmware 1.02.09 and can't upgrade because it's on the
> ISP. [...]

   If you're looking for reasons to complain about your ISP, ...

> I'd like to change the time zone [...]

   I'd suggest a Web or forum search for terms like, say:

      cable modem timezone

   I found, among many other things:

      https://community.netgear.com/t5/x/x/td-p/1916774

      "[...] the time is updated by the ISP and cannot be changed
      manually."

      https://kb.netgear.com/000061048

      "Cable Modem Routers use the time provided from the service
      providers [...]"