RevusHarkings |
You can't sacrifice open slots, only prepared spells.
PRD
PRD wrote:
A good cleric (or a neutral cleric of a good deity) can channel stored spell energy into healing spells that she did not prepare ahead of time. The cleric can “lose” any prepared spell that is not an orison or domain spell in order to cast any cure spell of the same spell level or lower (a cure spell is any spell with “cure” in its name).