Thanks for your kind reply. Please noticed that this drive firmware upgrade can be performed by upgrade engineer from EMC remote proactive team through remote session(ESRS/WebEx).
As a pre-check engineer from remote team as well, I would like to recommend your client to go with our remote team support as remote upgrade engineer are very professional and skillful on this upgrade task, also the task is a reboot less one with low risk and no downtime required at all.
However, if your side do prefer the onsite support for drive firmware upgrade I can help to dispatch the cases to our local team and let them further communicate and assist on upgrade for you.
Kindly awaiting your confirmation.