During WEST I met a lovely woman who loved my laundry paintings and especially liked one with my dog in it. It was too large for her, but a smaller one without a dog was just right except the missing canine companion. So I added her two poodle mixes in to this painting and updated the figure to look more like her.
Its so cool to be able to do that for someone and to know that the painting is really going to be valued and loved for years to come.
Don't hesitate to ask an artist if they can create something unique for you. Even if they are unwilling to change a finished painting, they surely will like to paint something similar and meaningful for you.