Dell PowerEdge M620 Owner's Manual page 277

NOTE:
If you are removing multiple mezzanine cards, label them so that you can
replace them in their original locations.
9 To remove a full-height blade system board:
Use the thumb and index fingers of your right hand to lift the system
a
board retention pin. See Figure 3-61.
Keeping the retention pin raised with your index finger, press the
b
corner of the blade chassis with your thumb to slide the system board
out of the open end of the chassis.
Installing Blade Components
277