Is there a simple way to convert bit depth to 16 bit?

I have code in Image Processor Pro that looks like this:

  // Bit Depth
  var bd = toNumber(task.@bitDepth) || 0;
  if (bd) {
    var bpc = doc.bitsPerChannel;
    try {
      if (bd == 8) {
        doc.bitsPerChannel = BitsPerChannelType.ONE;
      } else if (bd == 8) {
        doc.bitsPerChannel = BitsPerChannelType.EIGHT;
      } else if (bd == 16) {
        doc.bitsPerChannel = BitsPerChannelType.SIXTEEN;
      } else if (bd == 32) {
        doc.bitsPerChannel = BitsPerChannelType.THIRTYTWO;
      }
    } catch (e) {
      LogFile.logException(e, "Error selecting bit depth " + bd);
    }
  }

Then, later, I have this code which changes the document mode so that you can save it as a bmp file:

  if (ImageProcessorOptions.JDI && ext == "bmp") {
    // We need to make adjustments depending the number of
    // bmp save bits selected
    if (saveOpts.depth == BMPDepthType.ONE ||
        saveOpts.depth == BMPDepthType.SIXTEEN ||
        saveOpts.depth == BMPDepthType.TWENTYFOUR || 
        saveOpts.depth == BMPDepthType.THIRTYTWO) {
      saveOpts.rleCompression = false;
    }
    if (saveOpts.depth == BMPDepthType.FOUR ||
        saveOpts.depth == BMPDepthType.EIGHT) {
      doc.changeMode(ChangeMode.GRAYSCALE);
    }
    if (saveOpts.depth == BMPDepthType.ONE) {
      if (doc.mode != ChangeMode.BITMAP) {
        doc.changeMode(ChangeMode.GRAYSCALE);
      }
      var cnvtOpts = new BitmapConversionOptions();
      doc.changeMode(ChangeMode.BITMAP, cnvtOpts);
    }
  }

I don't think I've tested with pdfs files.

Hope this helps.