FTP download azure function

I have function for uploading a file to ftp and I woud like to know the equivalent function for downloading and renaming the file. I have no experience with c# I only use this functions to post them to azure function and then consume them in BC. I would be thankful is anyone could show or guide me to have the equivalent function for the download and the one for rename; Below is the upload function

[FunctionName("FtpStor")]
    public static async Task<IActionResult> Run(
        [HttpTrigger(AuthorizationLevel.Anonymous, "post", Route = null)] HttpRequest req,
        ILogger log)
    {
        log.LogInformation("C# HTTP trigger function processed a request.");
    
        string requestBody = await new StreamReader(req.Body).ReadToEndAsync();
        dynamic data = JsonConvert.DeserializeObject(requestBody);
    
        string fileUri = data.fileUri;
        string username = data.username;
        string password = data.password;
        string filename = data.filename;
        string ContentFileToBase64String = data.ContentFileToBase64String;

        var bytes = Convert.FromBase64String(ContentFileToBase64String);
        Stream fileStream = new MemoryStream(bytes);
        
        //Upload to FTP
        FtpWebRequest ftpWebRequest =  (FtpWebRequest)WebRequest.Create(fileUri);
        ftpWebRequest.Method = WebRequestMethods.Ftp.UploadFile;
        ftpWebRequest.Credentials = new NetworkCredential(username,password);
        ftpWebRequest.UsePassive = true;

        using (Stream  requestStream = ftpWebRequest.GetRequestStream())
        {
            await fileStream.CopyToAsync(requestStream);
        }
        fileStream.Dispose();

        using (FtpWebResponse  response = (FtpWebResponse)await ftpWebRequest.GetResponseAsync())
        {
            string result = response.StatusDescription;
            
        return response.StatusCode == FtpStatusCode.ClosingData
            ? (ActionResult)new OkObjectResult(result)
            : new BadRequestObjectResult(result);
        }

    
    
    }

And this the function that i'm using to call the ftp download :

RequestContent.Clear();
        Client.Clear();
        fileuri := 'ftp://*****:21/TEST/file.txt';
        uri := 'https://*****.azurewebsites.net/api/FtpDownload?';
        RequestBody := '{';
        RequestBody += 'fileUri:"' + fileUri + '",';
        RequestBody += 'username:"******",';
        RequestBody += 'password:"*****",';
        RequestBody += '}';
        RequestContent.WriteFrom(RequestBody);
        RequestContent.GetHeaders(RequestHeaders);
        RequestHeaders.Clear();
        RequestHeaders.Add('Content-Type', 'application/json');
        RequestMessage.Content := RequestContent;
        Client.Post(uri, RequestContent, ResponseMessage);
        ResponseMessage.Content().ReadAs(OutputString);
        tempblob.CreateInStream(FromInStream);
        FromInStream.Read(OutputString);
        Fromfile := 'file.txt';
        DownloadFromStream(FromInStream, '', '', '', Fromfile);