Hopefully i can help..
To reset the service/oil you need to carry out the following..
1. Press and hold the left odometer reset button while turning the key to position 1 (Accessory). Keep the button pressed for about 5 seconds until any of the following shows in the display: OIL SERVICE or INSPECTION with RESET or RE
2. Release the button and press it again for another 5 seconds until RESET or RE flash.
3. While the display flashes, press the button one last time briefly to reset the Service Interval. If done correctly, RESET / END SIA should show up for a few seconds.
Normally thats the way above on the E46's you have to try a few times to get it to work..the other option is via diagnostically and reset it that way this will also ensure no fault codes are present too..I do hope this helps..if you require to ask anything further then please do so before you rate