I just did a bunch of transactions yesterday. There are a total of 4 of us going to MCO from three airports on 4 different days. I had one person flying from BWI, but then the flights from PHL lowered briefly and I could move her. She's got two flights down right now, one early morning and one in the evening until she figures out her work schedule. I rebooked a return flight for another person. More points, but a more convenient flight. I had paid $ for my flight down and had already rebooked it and received a $27 credit. Yesterday my flight returning was lower, so I actually cancelled it and rebooked it for cash, using the credit I'd received. They must hate me at SW because I change so many flights. Guess I need a better hobby!
I love SW, it's so easy to check and change flights, especially on points. The hardest part is keeping all the reservation numbers straight. I do try to book both ways separately (because if you want to change one of the ways later, you have to call to get it done). I also do reservations for every one individually. While it's harder to check in at 24 hours, they don't always have multiple fares at the lowest price. So if you try to reserve 4 seats and there are only 2 at the lowest available price, you will get the fare that has 4 seats available. Plus it's easier to change if lower fares show up and aren't available for everyone in your group.