Spell Reprieve( Lost Empires of Faerûn, p. 9)
Your studies of the less restrictive arcane traditions of old allow you to cast one spell from a prohibited school.
Knowledge (history) 2 ranks, specialist wizard level 1st,
Choose a spell from one of your prohibited schools of a level that you can cast. You can now learn and prepare that spell normally.
You can take this feat multiple times, each time choosing a new spell from any of your prohibited schools.