Verb:RELEASE

RELEASE un-prepares a spell that has previously been prepared, either manually with PREPARE, via INVOKE from a scroll, or automatically through Rapid Fire (515) or Living Spell (208).

The mana cost of releasing a spell is 1/4 of its level, rounded down, with a minimum cost of 1 mana, except for Arcane Blast (1700) which costs no mana to cast or release.

Certain abilities such as Sigil of Escape are safer to use if any prepared spells are released first.