Save your image in Fireworks. Click "File" and then "Save." Type the name under which you wish to save your Fireworks image, and choose the format under which you wish to save your file in from the drop-down menu. Click "Save."
Click the "x" in the upper right-hand corner of the screen, or click "File" and then "Close" to close Fireworks.
Launch Photoshop.
Open your Fireworks file in Photoshop by clicking "File" and "Open." Click on the filename of your RGB Fireworks image.
Convert your RGB Fireworks image to CMYK by clicking "Image" and then "CMYK" from the pop-up menu. The color of the image may lighten just slightly. This is normal.
Save your CMYK image by clicking "File" and then "Save." Click "Save" in the save window.