The libero can replace ANY back row player. However, the libero may
only serve in the same rotation spot. For example, let's say #11, a
middle, starts the match in position two. When she rotates to
position one to serve, the libero can replace #11 and serve. On the
scoresheet you would draw a circle around the Roman Numeral II
indicating that the libero served in that position. For the
remainder of that GAME, the libero can only serve in that position.
She can REPLACE other players in other positions, but she can only
serve in that position. You do NOT need to designate which position
she will serve in prior to the game.

One step further...In the above scenario with #11 in position two
(front right) the libero would normally be in the game opposite #11
in position five (left back) playing for the other middle. When #11
rotates to serve, all she has to do is leave the court (BETWEEN the
attack line and end line) and the libero STAYS on the court and goes
back to serve. The libero does NOT have to leave the court in that
case.

Let me know if you have any questions.

Kevin