I imagine you are using a fairly recent version of ESXi, v6? From your linked KB:
ESXi 3.5, ESXi 4.x, ESXi 5.x and ESXi 6.xReinstalling the ESXi host is the only supported way to reset a password on ESXi. |
I would think doing this without proper access to the network resources required would be very difficult. I think exhausting all avenues to finding someone with the required passwords would be the best approach at the moment.