Dell Precision R5500 Owner's Manual page 58

22. Gently lift the heat sink off the processor and remove it from the computer.
23. Position your thumb firmly over the processor socket-release lever. Release the
lever from the locked position by pushing down and pulling out from under the tab.
24. Rotate the lever 90 degrees upward until the processor is released from the socket.
Rotate the processor shield upward and remove it.
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