By drivers armrest, are you referring to the one on the door or the center console? I'm having the same issue on all my 05 Amanti's doors. I actually sped up the process by using a heatgun to heat it up some and removed as much of the fake leather stuff that I could. The fabrics substructure doesn't look too bad when it's all exposed.

In terms of fixing it, I would assume if the area is small enough, you could try a normal leather repair kit. But I'm not sure if it will hold and it might cause more to peel off. If you're feeling adventurous, you could pick go to a fabric store and pick up some leather like material, take the door panel off, and replace the leather on the door itself. I haven't done that with the Amanti, but I've done it with other cars with fabric panels on the door.

 

Door panel material on these cars is very poor

So the door panel plastic coat is peeling from its fabric base? So far every first generation Amanti I have seen has done that. The previous owner removed the front panels and took them to the local upholstery shop. They patched the panels and spray painted the entire door panel to have one consistent gray color. They also over sprayed the gas door and trunk push buttons. The panels look like the speaker carpet has been torn away and re-glued, the Infinity badge on the speaker is frayed like a bell bottom jean dragging the ground on every step. So I think maybe this car is 13 years old with 140,000 miles on the odo. It is time to get out the spray paint, the glue and the nail clipper. A little superglue gel around the edge of the speaker emblem, should keep the fabric from fraying any more, and the rubber cement should stick the carpet back in place.
You can fix it to look pretty good yourself, or take it to the upholstery shop for a professional job.
Old cars are pay me later, new cars are pay me now. :laugh:

 

Arm rest

Thanks guys. It is the door arm rest.
Right now the black substance is "moving" along the substrate like a glacier. If you are old enough to remember the movie "the blob". If I do anything for now, it will be do nothing or put a piece of Gorilla tape over the area. I love the car, and I usually drive them into the ground but I'm a bit too old to go diving under the hood.
Can you tell me about what I can expect to pay to have it replaced by leather?

 

The cost is always going to differ due to many variables. Core cost of leather, markup from upholster, and labor. It's best to find a place near you that will redo the fabric on door panels and contact them for a quote. I try to do that kinda stuff on my own when I need to/can. This way I don't have to pay the labor charges and I get pride in a job well done.