From the digital meter installation instructions:
"To reset the indicator, press and hold the hourmeter/odometer/tripmeter select button and turn the ignition switch to ON for more than 2 seconds. The indicator will disappear."
"If the oil is changed before the oil change indicator appears, be sure to reset the oil change indicator after changing the oil. The indicator will appear for 2 seconds, then disappear. This means the indicator is reset."