Remove Oldest Modem From Account

I have 2 modems on my account and I want my oldest modem removed from my account. I can see the oldest modem is still on my account on the website. I have also tried using the app and going to the WiFi tab but all I see there is "You're online No outages found". I also tried using the Xfinity Assistant and it doesn't seem capable of handling this task. I think I need Xfinity staff to remove the oldest modem because I can't remove it myself with the available tools I have tried.