My Samsung Galaxy Nexus Verizon 4G, when I change the other simcard it will appear is the SIM LOCKED PUK, why is this and what can I do?

[AC Question]

my samsung galaxy nexus verizon 4G when i change other simcard it will appear is the SIM LOCKED PUK

MY SAMSUNG GALAXY NEXUS VERIZON 4G is having PUK SIM LOCKED..WHAT SHOULD THE BEST THING I CAN DO..