v24.5

    var options = new PdfAConvertOptions
    {
        PdfAVersion = PdfAStandardVersion.PDF_A_3B
    };
    // Add the source file
    options.AddInput(new FileDataSource("path_to_your_pdf_file.pdf")); // replace with your actual file path
    // Add the path to save the converted file
    options.AddOutput(new FileDataSource("path_to_the_converted_file.pdf"));
    // Create the plugin instance
    var plugin = new PdfAConverter();
    // Run the conversion
    plugin.Process(options);

    var regexes = new Regex[]
    {
    new Regex(@"(?s)document\s+(?:(?:no\(?s?\)?\.?)|(?:number(?:\(?s\)?)?))\s+(?:(?:[\w-]*\d[\w-]*)+(?:[,;\s]|and)*)+", RegexOptions.IgnoreCase),
    new Regex(@"[\s\r\n]+Tract[\s\r\n]+of:?", RegexOptions.IgnoreCase),
    new Regex(@"vested[\s\r\n]+in", RegexOptions.IgnoreCase),
    new Regex("Vested in:", RegexOptions.IgnoreCase),
    new Regex(@"file.?[\s\r\n]+(?:nos?|numbers?|#s?|nums?).?[\s\r\n]+(\d+)-(\d+)", RegexOptions.IgnoreCase),
    new Regex(@"file.?[\s\r\n]+nos?.?:?[\s\r\n]+([\d\r\n-]+)", RegexOptions.IgnoreCase)
    };
    var document = new Document(input);
    var absorber = new TextFragmentAbsorber(
    regexes,
    new TextSearchOptions(true)
    );
    document.Pages.Accept(absorber);
    // Get result
    var result = absorber.RegexResults