Dell PowerEdge C6145 Hardware Owner's Manual page 180

9 Remove the screws that secure the mid-plane holder support to the
chassis. See Figure 3-39.
10 Lift the mid-plane holder support out of the chassis. See Figure 3-39.
Figure 3-39. Removing and Installing the Mid-plane Holder Support
1 screw (3)
180 | Installing System Components
2 mid-plane holder support