Hi The13bats

Thanks for writing to Dell. 

When you say unlock do you mean to remove the minicard. If yes, then please follow the below link and page 41. 

http://downloads.dell.com/manuals/all-products/esuprt_laptop/esuprt_latitude_laptop/latitude-e6420_owner%27s%20manual_en-us.pdf

Do let us know if it helped or is there something else you are looking for.

Regards