Who I have the same questioned this topic

I traveled to the UK last week and upon landing bought a Vodafone SIM, which I put inside my iPhone 5s; the gentleman at the Vodafone store configured my phone for their network and it worked just fine. Upon returning to the US, I turned off my phone, replaced the vodafone SIM with my original Verizon SIM, and turned my phone back on. It connected just fine except I no longer get LTE signal; only 3G. I have tried soft booting, hard booting, and reset the network settings on my phone, but it has not obtained an LTE signal.

How do I get LTE back? Thanks!