Can I change the mode on WiFi

I have a fitbit Aria scale and it connects with band B but when I try to change it I am unable to so its just sitting at g/n bands greyed out because it wants me to edit on 

Xfinity xFi app or visit xfinity.com/myxfi

I checked everywhere an cant find where I can change this, kinda stupid I pay for this modem every month but cant do anything on it.