Spoke w/crew on 223 - they brought that aircraft in from IAD, which was also supposed to be 777 (during the six hour swap/unswap mess). Said the pax for IAD were really irate as many were upgraded based on the equipment change and then downgraded when the equipment was changed back. Also, observed people at SFO with seat assignments based on 777 who then found themselves w/different seats on the 757 - and not the ones they originally booked. Just a cluster, really. Felt bad for the crew, they were REALLY good, but had been beat up by this mess.