Auto body repair & detailing: blending paint, cheap insurance, sun light

Question
I had a fender installed and they painted the fender the color that the inside of the door says to use, but because the car is 5 years old the paint is a little darker than the older paint.  is there a way to buff or something that can reduce the difference in color?  its not horrible but in the sun light is noticeable. I appreciate any info on this. thx ray  

Answer
Unless they did a budget job for you, which is a favor, they should have color blended the door to match. All these base-clear paints were invented for that purpose. If you are not satisfied, take it back and insist that they blend the door. It'd darn seldom that I paint any side panel and don't blend into the panel next to it. It's cheap insurance against a come back, and the customer is always amazed with the "paint match". Little do they know I cheated! LOL. Bill