remove the option from your account via the verizon website. then add it back to your account via the verizon website. then reboot your phone.
Another option that can work (all from your phone):
settings > more > cellular networks > network operator
then i think you select 'auto' or something obvious. it might spit back an error or it might say verizon. either way once it finishes reboot your phone and the enhanced lte mode should be back.