Functions/Data/Format-UPN.ps1

Function Format-UPN
{
    [CmdletBinding()]
    Param
    (
        # Incoming Username to Reformat
        [Parameter(Mandatory=$True,ValueFromPipeLine = $true)]
        [String]
        $Username    
    )
    Process
    {
        # Derive Outgoing UPN
        $OutUserName = if ($Username -like "*\\*")
        {
            $UNSplit = $Username -split '\\'
            "$($UNSplit[0])@$($UNSplit[-1])"
        }
        elseif ($Username -like "*_*")
        {
            $Username -replace "_","@"
        }

        # Return Outgoing UPN
        $OutUserName
    }
}