Consider this a UCS 101 type of tip. Removing a server from a UCS Chassis is simple process, but it's one that may need a refresher for most people depending upon how often it's done. Whenever a blade is removed from a chassis, it's best to issue a decommission command. While easy to do, the option is buried under a sub menu called, "Server Maintenance." The words come from Cisco, I just provided a few pics to supplement the text.
Removing a Server from a Chassis
Step 1 In the Navigation pane, click the Equipment tab.
Step 2 On the Equipment tab, expand Equipment ➤ Chassis ➤ Chassis Number ➤ Servers.
Step 3 Choose the server that you want to remove from the chassis.
Step 4 In the Work pane, click the General tab.
Step 5 In the Actions area, click Server Maintenance.
Step 6 In the Maintenance dialog box, do the following:
a) Click Decommission.
b) Click OK.
The server is removed from the Cisco UCS configuration.
Step 7 Go to the physical location of the chassis and remove the server hardware from the slot.
For instructions on how to remove the server hardware, see the Cisco UCS Hardware Installation Guide for your chassis.
What to Do Next If you physically re-install the server, you must re-acknowledge the slot to have Cisco UCS Manager rediscover the server.