You need to let Home Assistant access your router’s settings, then. I don’t get why you want to do this, this shouldn’t need to be changed.
note: I misinterpreted the question as changing the IP of the device, instead of reconfiguring HA to use a new IP.
I can see a small benefit that HA could access some settings in the router, but given how many different routers there are, that is a big task.
And if HA does have that access then I believe IP settings is the lowest priority for me.
That’s not what OP is talking about I’m pretty sure.
When you add integrations/devices via YAML you set the IP of it, and can always see and change it when you open your config file.
When you add something via config flow, you tell it the devices IP but almost none of them allow you to see what IP it is using, or allow you to change it without deleting the entire thing and re-adding it.