If you have the graphics module installed, your interposer will have four screws. Otherwise, you'll have three screws.

Lift the pull tab on the interposer and let it rest vertically to access all of its screws.

Use a T5 Torx screwdriver to loosen the three captive screws securing the interposer.

If you have the graphics module, use a T5 Torx screwdriver to loosen the four captive screws securing the interposer.