Public/Licensing/Update-GSUserLicense.ps1

function Update-GSUserLicense {
    <#
    .SYNOPSIS
    Reassign a user's product SKU with a different SKU in the same product
    
    .DESCRIPTION
    Reassign a user's product SKU with a different SKU in the same product
    
    .PARAMETER User
    The user's current primary email address
    
    .PARAMETER License
    The license SKU that you would like to reassign the user to
    
    .EXAMPLE
    Update-GSUserLicense -User joe -License G-Suite-Enterprise

    Updates Joe to a G-Suite-Enterprise license
    #>

    [cmdletbinding()]
    Param
    (
        [parameter(Mandatory = $false,Position = 0,ValueFromPipeline = $true,ValueFromPipelineByPropertyName = $true)]
        [Alias("PrimaryEmail","UserKey","Mail")]
        [ValidateNotNullOrEmpty()]
        [String[]]
        $User,
        [parameter(Mandatory = $false)]
        [Alias("SkuId")]
        [ValidateSet("G-Suite-Enterprise","Google-Apps-Unlimited","Google-Apps-For-Business","Google-Apps-For-Postini","Google-Apps-Lite","Google-Drive-storage-20GB","Google-Drive-storage-50GB","Google-Drive-storage-200GB","Google-Drive-storage-400GB","Google-Drive-storage-1TB","Google-Drive-storage-2TB","Google-Drive-storage-4TB","Google-Drive-storage-8TB","Google-Drive-storage-16TB","Google-Vault","Google-Vault-Former-Employee","1010020020")]
        [string]
        $License
    )
    Begin {
        $serviceParams = @{
            Scope       = 'https://www.googleapis.com/auth/apps.licensing'
            ServiceType = 'Google.Apis.Licensing.v1.LicensingService'
        }
        $service = New-GoogleService @serviceParams
        $productHash = @{
            '1010020020'                   = 'Google-Apps'
            'G-Suite-Enterprise'           = 'Google-Apps'
            'Google-Apps-Unlimited'        = 'Google-Apps'
            'Google-Apps-For-Business'     = 'Google-Apps'
            'Google-Apps-For-Postini'      = 'Google-Apps'
            'Google-Apps-Lite'             = 'Google-Apps'
            'Google-Vault'                 = 'Google-Vault'
            'Google-Vault-Former-Employee' = 'Google-Vault'
            'Google-Drive-storage-20GB'    = 'Google-Drive-storage'
            'Google-Drive-storage-50GB'    = 'Google-Drive-storage'
            'Google-Drive-storage-200GB'   = 'Google-Drive-storage'
            'Google-Drive-storage-400GB'   = 'Google-Drive-storage'
            'Google-Drive-storage-1TB'     = 'Google-Drive-storage'
            'Google-Drive-storage-2TB'     = 'Google-Drive-storage'
            'Google-Drive-storage-4TB'     = 'Google-Drive-storage'
            'Google-Drive-storage-8TB'     = 'Google-Drive-storage'
            'Google-Drive-storage-16TB'    = 'Google-Drive-storage'
        }
    }
    Process {
        try {
            foreach ($U in $User) {
                if ($U -notlike "*@*.*") {
                    $U = "$($U)@$($Script:PSGSuite.Domain)"
                }
                Write-Verbose "Setting license for $U to $License"
                if ($License -eq "G-Suite-Enterprise") {
                    $License = "1010020020"
                }
                $body = Get-GSUserLicense -User $U
                $request = $service.LicenseAssignments.Update($body,$productHash[$License],$License,$U)
                $request.Execute()
            }
        }
        catch {
            $PSCmdlet.ThrowTerminatingError($_)
        }
    }
}