While this may not help much, Photoshop can handle palettes as well, import and export them, and easy editing.
You can do all of this via Image > Mode (Modus) > Colortable.
From there you can edit, load and save palettes (supported extensions are .pal and .act). Though the image mode has to be indexed (which should already be the case anyway).
Indexed mode means that the image has a set palette and cannot be changed without changing the palette itself (what I just explained).
Just tried to be helpful~