using System;

public class Program

{

    public static void Main()

    {

            ClientContext ctx = new ClientContext(serverURL);

            ctx.Load(ctx.Web);

​

            Web web = ctx.Web;

​

            Uri filename = new Uri(URLtoServerSUM);

            ctx.ExecuteQuery();

​

            FileInformation fileInfo = Microsoft.SharePoint.Client.File.OpenBinaryDirect(ctx, filename.AbsolutePath);

​

            Microsoft.SharePoint.Client.File file = web.GetFileByServerRelativeUrl(filename.AbsolutePath);

            file.CheckOut();

​

            using (FileStream fs = System.IO.File.Create(localFile))

            {

                fileInfo.Stream.CopyTo(fs);

            }

            //Modify localFile as needed

​

            ctx.ExecuteQuery();

​

            using (FileStream fs = new FileStream(localFile, FileMode.Open))

            {

                Microsoft.SharePoint.Client.File.SaveBinaryDirect(ctx, filename.AbsolutePath, fs, true);

            }

​

            file.CheckIn($"Updated by automatic SUM table generation on {DateTime.Now.ToString()}", CheckinType.MinorCheckIn);

​

            ctx.ExecuteQuery();

    }

}