RELEASE by itself will release harnessed mana, a prepared spell, and an active cyclic.
RELEASE ALL: same
RELEASE SPELL: releases spell being prepared
RELEASE CYCLIC: releases your active cyclic spell
RELEASE MANA: releases all held mana
RELEASE # MANA: releases a specific amount of held mana
RELEASE <spell>: releases a spell that you've cast on yourself
RELEASE SCROLL <spell>: releases a scroll you've INVOKEd
RELEASE CANTRIP: releases any cantrips you are preparing
RELEASE <cambrinth item>: releases your connection with the mana stored in item.