Well, I guess you'd de-solder the old one, then solder in a new one. Unless it's surface mounted. That could be a bit trickier. In any event, it will require MAJOR disassembly to get to the bottom side of the port if need be. Might want to take it to a pro, but it's gonna be an expensive repair.
EDIT: After looking at photos of the motherboard, it appears that all the tabs that need to be desoldered/soldered DO pass through the motherboard (which is good). It's something I'd be willing to tackle if it was mine. Did the jack break, or just start to come loose from the board?