How do I access the WWAN module for maintenance or change in an HP ProBook 640 G2?

To remove and potentially replace a WWAN module: Start by powering down the system, disconnecting all peripherals along with shutting off power supply entirely. Proceed to disassemble starting from service door opening sequence followed by battery, hard disk drive unit (including SSD if present), WLAN/MIF card, optical drive removals sequentially before reaching to the installation of WWAN module where you will unhook two connecting cables and loosen screw holding it firmly in place for replacement if required. Reassembly must follow these steps precisely in reverse order. (Page 42)