Originally Posted by EarlyMon
Unfortunately, you're not going to.
AT&T pulled this same stunt last year on the HTC One X.
With that, the only option was to create a new APN. That would turn off 4G services - but leave the LTE radio powered up.
And even that - I think - got killed by an update to that model.
There's a service/test code setting outside of the normal menus that will let you get to the option - except on an ATT model, you can't make the setting stick even when you can see it.
The only solution that I think you'll really find is to find a rom with a 4G toggle appropriate to the ATT model, root and apply that.
Now this really pisses me off...
Glad I went to Android OS with it's infinite customizable platform compared to iOS....
I use my phone to stream audio 5x more than I use it for anything else. I thought I did my due diligence prior to the shift and though I was willing to give up the integration of iOS (with vehicles, devices, accessories etc) to gain a better screen and the ability to customize.