You don't need a scanner to reset the oil change interval. That is done using the buttons near the speedometer. The instructions are in the owner's manual. There is also a YouTube video that explains how to do it.

I've owned a '98 e300 for more than 10 years and have reset the interval several times. I can't remember what I did. The last time, I went to the video as I could not fine my owner's manual.

There are a number of helpful YouTube videos for various w210 repairs and maintenance.