1) Have the car completely off (take out key, open door, close door)
2) Put key in ignition
3) Press and hold 0.0 button on dashboard
4) Turn the key to the On position (but don't crank the engine) and release the 0.0 button
5) A message asking if you want to reset the oil service interval will appear
6) Press the 0.0 button to confirm
7) You will see a cofirmation message saying the oil service interval was reset to 365 days
BTW, I had the same, normally 20k interval, last service they set it to 10k "accidentally"... I had to go in and have them add another 10k interval...
But you could use the above if you want to stop the damned thing binging all the time ;-)