Hi, I have re painted leather with excellent results.
I cut a tiny patch from an inconspicuous part, of the underside of a chair. Sent it to a leather dye company, and they sent out the relevant stuff in a kit.
It was very easy, and the chairs looked brand new after. Most of these places sell products that restore but, keep the aged look if needed. My needs were just for a revamp on six very comfy dining chairs.