With the midframe removed, it is also possible to replace the M.2 SSD during this step

The hard drive is underneath the heatsink so the heatsink must be removed

Fully loosen (they don't come out) the four spring loaded torx screws labeled 1 to 4;

Remove three torx screw labeled 5 to 7

Remove 5mm hex mounting post

Use a spudger to remove the heatsink assembly from the motherboard