Arrived at customer home to inspect a leak coming from first floor lav drain. Upon arriving I noticed customer had a special style of sink that I was unfamiliar with I asked customer if they knew how to remove the vanity covering the pipe. CUSTOMER TOUCHED SINK WALL AND WALL CAME APART. I then inspected the sink more and noticed that a section of the sink just comes up. Removed top section of the sink and disconnected drain and teflon every thread and applied plumbers putting to sink drain. I then out every back together and tested drain. Drain wasn’t leaking. Customer will get a contractor to make repair to sink wall.