With Pizzicato Professional,
when you place the octava symbol (upper or lower), its influence
is to transpose one octave starting at the symbol position. If
you want to limit its effect to a fixed duration (and not for the
rest of the score), modify the options of this symbol. In the
score, click this symbol while holding down the CTRL key. Click
the "Full editor" button. Check the "Local
change" box to the right of the dialog. On the left of the
dialog, you will find 3 text boxes which let to determine the
duration of the effect, in number of measures, beats and units
(480 units for a quarter note). Click OK. The transposition
effect will last as long as you specified it.