IBM FC EJ08 Manual page 24

Figure 7. Removing the side cover from the PCIe adapter cassette for the 9080-M9S system
6. Remove the top cover from the cassette.
a) Press the release button on the top cover and slide the cover in the direction that is shown.
b) Lift the top cover off the cassette.
10 Power Systems: PCIe adapters for the 9080-M9S