To remove power from a COB while installed in a shelf, slightly pull the right handle out just until the blue LED is lit.
To restore power to the COB, press the right handle in until the blue LED turns off.
For more details, see page 15 of the following workshop presentation:
RPT_Workshop_Shelf Installation_Networking_and_Administration.pptx
See also COB RCE Reset and COB Cold Data Reset