Seeing into the future and reaching into the past the diviner is able to prepare the right spell for the right circumstances. Channeling divine magic the wizard reaches into her spellbook and alters reality slightly to modify the prepared spells in her mind.  

Replace one prepared spell of same or lower level than this spell with another spell in your spellbook. The newly prepared spell cannot be of a higher level than Andrea's Divine Preparation nor can it be higher than the spell it replaces.  

If this spell is cast at higher levels the spell prepared/replaced can be of an equal level. E.g. upcasting Andrea's Devine Preparation at level six allows you to replace a spell of level six or lower.