The only way to RESET any appliance is to remove it from the power source. Unplug or trip the breaker for at least 30 seconds then plug back in .
The 1-2-3 method is a diagnostics tool, not a reset. The first 2 tests will flash E-? F-? Those are errors that have happened and will be displayed once then deleted. This Diagnostics mode tests all circuits, components, sensors etc. .The results of each test are displayed with lights in a certain sequence on the display. Not all models have the same sequence or display. Unless you have the diagnostics mode info, this test is useless.
Some posts I read said the "1-2-3 "worked. They might have had an error code displayed and in diagnostics mode the code was cleared. Some errors will clearand appliance will work, until the error happens again.
If lights are flashing and it won't start- determine what the error is then clear the error.