there is an LTE app on the playstore which works on our phone where you can set up the type of network you want to use.
or in the network options don't you see something.
unfortunately you cant flip between LTE and 3G yet on Android 4.2.2 but you can make the phone use 2G
This feature is added to 4.4 KitKat so it will be available to Moto X soon.
So, like others said you have to use an app from play store.
if you are looking to completely switch off data you can use app like power toggle.