I know nothing of the Jargon for changes and updates, but someone here from Flow or Flightplans would know. What I can say is that changing (CHG) the level would certainly issue a new slot (or cancel old one) as the levels can obviously take you into being flowed by another sector, or even centre. More and more companies are now playing around with their flightplans to find a different route or level which will give them an earlier slot. Still, can't get over the day we had a DLH Man-Munich via Veule at the same time as Bristol-Nice via KOK, surely someone could have intervened a bit (both after same cruise levels too!!!)