I want to know how to convert w124 400e seats to w124 300ce seats so the top part of the seat folds?

Thanks

Find coupe seats at a junkyard. Remove the upholstery from them, and install that from your current sedan seats.

i'm curious too, but i heard it can just be done with a screwdriver, and all you have to do is reroute the vacuum, and make a new hole