You can use this function to manually correct pictures that are suffering from tinting due to bad white balance settings during picture-taking.
To reach this window, use Edit | Adjust | Adjust Color Temperature… [Ctrl+2] in the Browser window, or Adjust | Adjust Color Temperature… in the Editor menu. You can define the color temperature by setting a neutral color or by entering a color temperature.
By manually setting a neutral color lets you set a "gray" point. This is a pixel that should have no tinting after the edit. You cannot use for this purpose a point suffering from maximum blowout (a pure white pixel), because no color shift can be determined on the basis of pure white.
You can set a lighting temperature using two sliders. The first slider is for shifting colors based on the picture's current lighting temperature, from blue to yellow. The second slider is for correction from green to purple.