Found out a few things recently and wanted to share. It seems SAS does use the ATC module by Amadeus and agents are instructed to religiously follow it and not change anything. Worst of all, the tickets issued by travel agents get reissued and as a result they cannot make changes for their clients once the ATC had done its work as the ticket goes to SAS' control. LH group does it a bit differently, there the agents are allowed to make changes and change the ticket themselves within the limits set by ATC.