This is a quick PowerCLI script that reads from a list of VM names and for each VM with network adapter type “E1000” changes it to “Vmxnet3”. Nothing fancy, no reboot is needed. MAC should stay the same, but this depends on your cluster network configuration.

Set-PowerCLIConfiguration -Scope Session -WebOperationTimeoutSeconds -1 -Confirm:$false;
Import-Module VMware.VimAutomation.Vds;
$VMHost="vcenter01.domain.com";
Connect-VIServer -Server $VMHost -User 'DOMAIN\User' -Password 'Password1';

foreach($line in Get-Content C:\vm_list.txt) {
Get-VM "$line" | get-networkAdapter | Where { $_.Type -eq "E1000"} | set-NetworkAdapter -Type "Vmxnet3" -confirm:$false
}