Never tried it, and really you should use new fretwire as you will probably damage or twist the old one getting it out. But if you do try, make a mark so that you know which way it's currently facing, but put it back facing the other way. The barbs on the tangs should then be in a different place, so it should grip the sides of the slot again. Putting it back in the same way it will be loose.
Run a hot soldering iron over the fret first in case it's been stuck down with glue, and that should help free it. Then you really need some fret-pulling pincers with a ground side to them (so the edges are both sharp and the right next to the fretboard). Something like these:
You should initially grip the base of the fret and not try to get the edges of the pincers under the fret until it's raised up a bit. This is when you'll probably scratch or twist the fret.