Reset engine light

Hi newbie here, my wife got a sienna and the serive light came on. She took it to the dealer and they said the light comes on every 3000-4000 miles for an oil change. I change my own oil. The dealer told my wife she needs to bring in a recipt of the oil and they will reset the light. How can I reset the light myself ? Do I need a code reader to reset it ?

I feel like I'm the only one out here.
Autozone and most other autoparts stores will clear an engine code for you. You can get a code reader yourself for less than it costs to have a dealer clear a code twice. Make sure you have a pencil and paper with you to write the code down before you clear it. Service manuals for vehicles give more complete descriptions of the codes and can be useful.

hold on the trip odometer reset button and turn the key to the run position but do not start. Keep holding the button for a few seconds and release it. This resets service maint light.