New Modem installed, but old modem is still on account

I have a certified Next-Gen Hitron CODA56 modem. It is pulling a legacy bootfile and capping my speeds.  Of primary concern is the upload speeds, it is only at 40 Mbps. How can I have my old modem removed from my account entirely, re-add the new MAC address, and push the Next-Gen bootfile?

Do I have to call customer support for this or is there an online way of doing this?