How common is it for the aircraft to keep changing before departure. Yyz-yvr booked in March for a May trip. Started out as a airbus a330-300, switched to a 777-300 with a smaller J cabin. Now switched to the second layout of the 777-300 with 2 J class cabins. Just wondering if i should expect it to keep changing. Only wondering because I have had to move our seats each time to sit in economy in a 2-4-2 area of the plane