It has to be done with a scan tool. Resetting the light without correcting the problem will be of no use as the light will come back on.
You did not say what year it is. In general you can get an OBD reader that plugs into the port on the car and use that to reset the codes by erasing them, OR you can pull the fuse on the ECM or you can disconnect the battery. If the light does not go out when any of these are done then the issue that made the light come on is not corrected.
There are a multitude of reasons why the check engine light could come on - you need to have an OBDII scanner hooked up and pull fault codes to determine the cause. As for resetting it, fixing the problem which causes it would be the best way to go.
You will need to take the 2006 Audi A6 to a mechanic to have the service light properly reset. In some cases, a person can undo the battery to reset the light.
To reset the service light on a 2009 Audi TT, first, turn on the ignition without starting the engine. Then, press the gas pedal fully three times within 10 seconds. After that, turn off the ignition and start the engine to ensure the service light has been reset. If the light remains on, you may need to repeat the process or consult the owner's manual for further instructions.
To reset the warning light on an Audi A3, first, turn on the ignition without starting the engine. Then, navigate to the vehicle's menu using the multi-function steering wheel or dashboard controls. Look for the "Settings" or "Service" menu, where you can find the option to reset the warning light. Follow the prompts to confirm the reset. If the light persists, it may indicate an underlying issue that needs to be addressed.
Indicator lights on an Audi can be reset by a mechanic. The cars manual will also give instructions on how to reset this light as well.
by going to an AutoZone store and having them reset it with their handheld computer system that plugs directly into the information port under the dashboard on the drivers side
with a dignostic tool
Click the link.
I Think its a main dealer job only as they use a guided function with the Audi VAS computer to reset the service display
maybe the plug under your seat has been unplugged, you will have to check the connections and then get the computer system reset using vagcom by an Audi dealership to see if that has resolved the problem