You can open a ticket at a low severity for this, so if you do end up needing support it will save you sometime. You'll need a valid service contract number for the equipment in question. Provide them the same information as you would if you were opening a case. Instead let them know it is proactive and provide the date and time of the schedule work. I think 2 or 3 days in advance of your scheduled work is sufficient. It is not like they are going to have someone sitting there waiting for you, but it will be faster than starting a fresh case.
Typically, when you do this you will not need their help. As long as you gracefully show down the VMs and the CIMC you should be fine powering it back on.
