To answer your question so that you donøt need to call, the KtN can only be entered during OLCI. Or at the airport. To save time and avoid agent typos, I do OLCI just for this reason.

The SAS phone number from the US is 800 2212350. I know it by heart and it hasnøt changed since the 1980s. In the old days they had well informed Swedish ladies working out of Long Island, IIRC. Today, they have outsourced people in Cyprus or Poland who are clueless and will create problems with you reservation if you call them. And they probably have not idea what KTN is in the first place.