FunctionsPublic/Set-GraphGroupDisplayName.ps1

function Set-GraphGroupDisplayName
{
    param([psobject]$accessToken, [string]$groupID, [string]$newDisplayName)
    #
    # Create new unified group
    #
    $sendBody = @{
        "displayName"= "$($newDisplayName)"
        } | ConvertTo-Json 
    
    $responseBody = Invoke-RestMethod `
        -Uri "https://graph.microsoft.com/v1.0/groups/$($groupID)" `
        -Headers @{"Authorization" = "Bearer $($accessToken.AccessTokenCredential.GetNetworkCredential().password)"} `
        -Body $sendBody `
        -ContentType "application/json" `
        -Method PATCH

    $jsonResponse = $responseBody | ConvertTo-JSON

    $createdTeam = ConvertFrom-Json -InputObject $jsonResponse

    return $createdTeam
}