Changing the color of the stripes in a flag

To me this sounds like classic overexposure and clipping.

Sometimes (if it's not completely clipped in the sensor) the color can be brought back with the Highlights slider.

If the stripes are hue shifted, then chances are the rest of the image is also is hue shifted. If so, the first thing to try is to adjust the overall Temperature and Tint to correct the whole thing, not just the flag. However, if most of the picture looks OK and it really is just the flag stripes that are wrong, I’d suggest setting up a Color Range mask targeting the yellow, and using that mask’s Hue adjustment to shift the hue to red, as in the demo below. The steps are:

1. Create a Color Range mask.

2. Click the yellow color with the eyedropper to sample it as the target color. The yellow stripes become red but this is not an actual color change yet; it’s just a red color that indicates where the mask has been created. The actual image color doesn’t change until the next step.

3. Adjust the Hue value until it’s the red color you want.

4. If it needs to be darker or lighter, also adjust a tone option such as Exposure.

5. If some yellow parts were left out, update the mask to include them. I did this by dragging the Color Range eyedropper, this time with the Shift key held down to add to (not replace) the selected color range. You can see the eyedropper is in Add mode because the pointer has a + sign next to it.

If this unintentionally changes yellow colors outside the flag that you don’t want to change, use the Intersect mask mode to combine the Color Range mask with an Objects or Brush mask to restrict the change to the flag.

You can try Point Color, but its hue adjustment range might be too narrow. Hue is good for large moves like this one. Point Color was recently added for more precise and subtle adjustments like for skin tones, for when Hue is too much of a blunt instrument.

You can try to do it with the new point color function in LR:

https://youtu.be/M9ERABfu-Yg

Here is another tutorial how about change colors:

https://youtu.be/-5UYY5geLxs