Turnig of the LTE

How do you turn off the LTE on a ATT Samsung phone?

Welcome to Android Central! Tell us exactly which phone you have. Are you trying to turn off mobile data, or do you just want to use 3G instead of 4G LTE?

Not entirely sure if this is relevant here but under Settings /WiFi and Mobile Networks there should be an option about network mode. Possibly even options similar to what I have below. You may have an option for GSM only or GSM /hspa+ or LTE.