With easyjet, is it possible to return with a different hold bag than was taken at departure?

On our easyjet flight, we have booked one hold bag so far, as of the three of us going to the Algarve, one of us is staying out there to work, whereas the rest of us will be buying things such as snorkeling kit, shirts etc. We were planning to flat pack a soft case in his hard case going out there and then remove it and fill it with our souvenirs, but are unsure if we can do this. Is anyone familiar with easyjet to the extent taht they know if this is possible? Has anyone done this before? Any help would be appreciated!