There is no rename PowerShell cmdlet on veeam v12. So here is my workaround to maintain the same backup job. If I use the clone backup job name, it will perform an active full when scheduling the job run. This is a norm scenario as the backup job name has changed and existing backup data cannot map.
# Connect to the Veeam Backup & Replication server
Connect-VBRServer -Server "VBR12GA"
# Get the backup job you want to clone
$sourceJob = Get-VBRJob -Name "VmwareVM-DC01-demodomain"
# Get the new proxy server
$newProxy1 = Get-VBRViProxy -Name "proxy1.veeamlab.local"
$newProxy2 = Get-VBRViProxy -Name "proxy2.veeamlab.local"
#update proxy
Set-VBRJobProxy -Job $sourceJob -Proxy $newProxy1, $newProxy2
# Specify the name for the cloned job
$clonedJobName = "ClonedJobName-Lai"
$clonedJobNameOriginal = "VmwareVM-DC01-demodomain"
# Clone the backup job
$clonedJob1 = Copy-VBRJob -Job $sourceJob -Name $clonedJobName -Repository "Default Backup Repository"
Remove-VBRJob -Job $sourceJob -Confirm:$false
$clonedJob2 = Copy-VBRJob -Job $clonedJob1 -Name $clonedJobNameOriginal
Remove-VBRJob -Job $clonedJob1 -Confirm:$false
# Save the cloned job
Set-VBRJobOptions -Job $clonedJob2
# Disconnect from the Veeam Backup & Replication server
Disconnect-VBRServer