With the LCD screen, just push the LCD knob to reach the main menu.
Depending on the language your are using select "Stop print"
IMPORTANT: Wait a few seconds until the hot end temperature is below 70°C. If you stop the power supply when your hot end is still hot, the plastic inside the hot-end will expand and will cause your next prints to fail.
If a dangerous event happens, shut down the power supply, wait a few seconds and power it on again so that the fan attached to the heat sink of the hot end start cooling it again to prevent the plastic from expanding.
IMPORTANT: Before restarting your printer, make sure that the height of the hot end nozzle is at least 3 or 4mm above the heat-bed!. Indeed, at the next print, the homing procedure will move the hot-end on X and Y axis and then Z axis. If the nozzle is too low, it’s likely to scrap your polyamid tape or even your print surface.