The X32 has multiple expansion cards available. Such options as the X-ADAT card, X-MADI card, X-Dante and X-UF card. All X32 mixers ship with their own X-USB card.
To remove the card it is a very simple process. Make sure the X32 is powered off. The card slot resides at the back of the unit. There are 2x cross head screws at the far left and far right of the card that screw into the chassis of the X32. Simply remove these and the card will pull right out. *Note that there are also 3x smaller screws at either side and the middle of the card but closer in than the bigger ones. Do not remove these as they are screwed into the card's PCB.