How do you turn off a maintenance required light?

To clarify, if you are referring to the Check Engine Light use and OBD2 scan tool to reset the light after the repair. But I assume you are NOT talking about the Check Engine light and are referring to the Maintenance Required light. If so, it Depends on the vehicle. On most Hondas press and hold the odometer reset button while at the same time turning the ignition to the on position without starting the engine. The light will go out in 5 seconds. On other vehicles you use the same or a different procedure. You failed to list the make, model, and year so that is all I can tell you.