1. Open the file
3. Apply Noise reduction to the entire photo. You may use any noise reduction filter you like. I prefer the Reduce Noise Filter.
4. Apply desired amount on the noise reduction. Since my photo has a lot of visible chroma noise on the dark areas and contains visible luminance noise I choose to put the amount to full. I can adjust the amount of noise reduction on the dark areas later.
For comparison I have attached the before and after image of the file