Mystic: Signature Spells

You've learned to cast some of your spells more flexibly, granting you extra control over your spellcasting. For each spell rank you have access to, choose one spell of that rank to be a signature spell. You don't need to learn heightened versions of signature spells separately; instead, you can heighten these spells freely. If you've learned a signature spell at a higher level than its minimum, you can also cast all its lower-rank versions without learning those separately. If you swap out a signature spell, you can choose a replacement signature spell of the same spell rank at which you learned the previous spell. You can also retrain specifically to change a signature spell to a different spell of that rank without swapping any spells; this takes as much time as retraining a spell normally does.