Disconnect the cable from the extruder that contains three wires for the fan, motor and heater block.
Use a 2.5 mm hex bit to unfasten the screw and release the extruder mount assembly.
Unfasten the two screws that are holding the fan to the extruder mount.
Turn to the mount on it's side, switch to a 3mm hex bit and loosen both screws from the assembly.
Move the extruder and motor aside. The metal mount plate is attached the nozzle and heater block.
Remove the mount plate by unscrewing the the two 2.5 hex screws from the wooden aligners.
The mount plate is aligned to PTFE tube, use slight force to pull the plate off.
Use a sharp needle to poke out the left over filament remaining around the PEEK Isolator.
Switch out the 3mm PTFE and switch it out for the 1.75 version. Slide on each heat sink blade and washer.
Hold the plate on top of the wooden aligner and add both screws to reassemble.