I'm not sure, but I think it has something to do with acquiring your new property within a certain time period after selling your old property? There's a tax deferral or something if it's done within the time period.
correct, or you can do it the other way too, get your new one before you sell your old one like i did. Heres where i messed up, you cannot actually close and take the title of your new property. instead you have a title company hold it in escrow until you sell your old property. well i closed on my new property already...dumbass move.