How do I fix laminate flooring that's begun to rise in the middle?
Depending on the layout, you might be able to fix this without taking up any of the flooring.  Here in the US at least, laminate flooring is usually installed in a floating manner, where the individual laminate boards are not attached to the subfloor at all and the entire floor is free to expand and contract (assuming it's not bound up at the edges).  The expansion gap around the perimeter of the room is hidden under a baseboard and some variety of quarter-round or shoe molding.

If your floor is buckling because its expansion gap isn't big enough, you should be able to remove that shoe molding and baseboard and cut the edges to increase the gap without pulling up the flooring.  I'd recommend an oscillating multifunction tool for this as it will let you cut very close to the wall, unlike a circular saw.  Here's a cheap one from Harbor Freight.