Reset the current program 

If you want to reset the micro:bit program that is running, you can press the reset button on the back of the micro:bit device and the current program will start again.

Stop the current program

If you want to stop the program running, just disconnect or switch off the power source to the micro:bit

Erase the program

If you want to erase the current program completely, simply flash the micro:bit with a new program or reset the micro:bit to it's factory default program.