I'm booked in Premium Economy on a 777 route next week and was able to choose my seat at the time of booking. Today, I checked to choose a better seat for my connection to Amsterdam and discovered that the Premium Comfort seat map is "not available" on KLM's website. Same applies to Expertflyer, which returns an error message for this zone but provides seat maps for Business and Economy which are compatible with a Premium Economy-equipped aircraft (e.g. 9 rows of Business and Economy starts at Row 17). Am I just being paranoid to suspect that KLM may be looking to swap with an aircraft without Premium Economy? No seat are assigned in Business beyond row 6, which would fit with the PE-less configuration. Expertflyer class availability is J5 W8 Y9. Does this type of swap happen frequently, and if so, how do they handle the situation?