Five years ago I paid an upholsterer a lot of money to re-upholster the seat in my 1979 pickup with blue leather. She bought a whole cow hide that was blue color, and she did a very job. She sewed a big Chevy bowtie on it, and it looked great. But the color has faded a lot, and now it is an ugly greenish color that I don’t like at all. What can I do to change the color of the seat? I would prefer to make it a blue color; but dark grey or black would be okay.