countparas, You can not change the cars computer settings with out special scanner/software/knowledge as normally found at a dealership or well equipped shop.
Ask the dealer ship/shop to show you the cars idle speed specifications cold/warm(operating temp.), if idle speed is in the parameters should probably not adjust further. If not in parameters they should correct the issue. Whether by adjustment/faulty sensor, vacuum leak,throttle body sticking/dirty or having to change program in computer. Good luck. I hope this helped you out, if so let me know by pressing the helpful button.