Replace the line don't try to flare the end of an old line if you haven't done this before. As for the line wrenches they look like a six point wrench with a slot cut out on the end for the line to slip thru. Now when you go to remove the other end of the line that you cut here is my suggestion. Get some Kroil or PB Blaster penetrating oil. Soak the fitting a day or two before you try to remove. Lightly tap the fitting as this vibration will help the penetrant work into the threads.
