Dell Precision T7400 (Late 2007) - Manual (Page 203)

Adding and Replacing Parts 203
3 Press the tabs on either end of the card retention device and lift to remove
it from the computer.
4 Press down the tab on the top of the card retainer at the appropriate card
slot and pivot the card retainer back through the chassis wall.
1 card retention device 2 tab
1
2