Upon arrival, customer informed me that she had a leaking showerhead and they tried multiple times to replace the cartridge. It was not successful. I advised customer that I would need to do a brief diagnostic and after diagnostic that determined that I would need to replace the cartridge, however the customer did supply the cartridge and it was the right one. After disassembling the shower trim I removed the Delta cartridge and replaced it with the current customer supplied cartridge and reassembled the shower valve trim. I turned the water back on, and there were no leaks. Customer was very satisfied.