Color pixel swap

So, we're only a few chapters in before we start the real stuff. I need to read all the pixels (x,y) and if they are red, make them blue and vise versa. I'm just not getting the dbDot code right. Can someone take a look and point me in the right direction?

Code:

//Chapter 6 exercise 4, red & blue pixel swap.
#include "DarkGDK.h"

//*************************************************
// DarkGDK function                              *
//*************************************************
void DarkGDK()
{

   // Color constants
   const DWORD  RED = dbRGB(255, 0, 0);
   const DWORD BLUE = dbRGB(0, 0, 255);
   const DWORD GREEN = dbRGB(0,255,0);

   // Variable to hold pixel color.
   DWORD pixelColor;

   // Width and Height variables.
   int width;
   int height;

   // Variables to hold red, green, and blue components of RGB color.
   int redChannel;
   int greenChannel;
   int blueChannel;
   
   
   // Extract the red, gree, and blue
   // components of the color.
   redChannel = dbRGBR(pixelColor);
   greenChannel = dbRGBG(pixelColor);
   blueChannel = dbRGBB(pixelColor);


if ( dbFileExist("record.bmp"))
   {
      dbLoadBitmap("record.bmp",0);
   }
   else
   {
      dbPrint("ERROR: record.bmp does not exist.");
   }

   dbPrint("Press any key to continue");
   dbWaitKey();

   // Get the images width and height.
   width = dbBitmapWidth(0);
   height = dbBitmapWidth(0);

   for (int x = 0; x < width; x++)
   {
      for(int y = 0; y < height; y++)
      {
         pixelColor = dbPoint(x,y);

         if (pixelColor == BLUE)
         {
            dbDot(x,y); RED;
         }
            else if (pixelColor == GREEN)
            {
            dbDot(x,y);GREEN;
            }
               else if (pixelColor == RED)
               {
               dbDot(x,y);BLUE;
               }

      
      }