they will have to be unstacked slowly .I would be ready with a tarp and wrap it around the dirt and stack it to the ground behind the pond to help hold back the dirt .Thing is putting it back together .
Luckily the liner runs all the way to the top of the wall and about a foot beyond. I can take off the top section of rocks and the liner should hold the dirt well as long as I keep the liner secured at the top and just run the new liner over it. Then carefully restack the wall.