Afaik there is no API or command that performs that DCUI functionality.
You can reset your network configuration through the Get-EsxCli cmdlet, but the problem there would be that you are cutting off the branch on which you are sitting.
See for example a set of esxcli commands in ESXCLI Basics: Troubleshooting Management Network Connection on ESXi 5.x
On a side note, isn't a restart of the ESXi node picking up the MAC change?
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