I have an Actiontec MI424WR Rev D FIOS Router that Verizon provided when I had video and internet and wireless together. I have since downgraded to internet only and Frontier has taken over as my FIOS provider. Really want to get off of this router and upgrade to a newer router. My ONT has coax and wan cables running to router. Can I disconnect the coax and wan connection and replace it a newer model router? My internet plan currently is 50/50.
Welcome to the forums. You're talking to other users here. Most of us are Verizon users, so we don't know much about how Frontier works these days. You may want to look for Frontier forums (I don't even know if they have any.)
That said, that's a really, really old router. You should get rid of it ASAP, as it's likely full of security vulnerabilities including insecure WiFi.
If Frontier is anything like Verizon, you should be able to get the ONT provisioned for Ethernet WAN. From your description, this might even be the current case; but you didn't give enough info to confirm. Once the ONT is provisioned for Ethernet, you can use any router you like. In Verizon land, this has support implications. Check with Frontier to find out how they handle user supplied routers.
Reason I went to this forum is because the ONT was replaced when I upgraded to TV from the original FIOS configuration and they ran a WAN ethernet and Coax cables to the router. Verizon was still my provider when I discontinued the TV function. Frontier replaced Verizon as my FIOS provider. Nothing has changed to my hardware only billing from Verizon to Frontier since April 2016 so I think it would be fairly easy to replace my Actiontec router with a new router.