Prerequisite: the ability to learn and cast spells from the list of Wizard's spells.

When a spellcaster can learn or prepare a spell, the spellcaster can choose to convert a cantrip into a level-one spell. The converted cantrip is memorized by the spellcaster in this converted form until the spell is forgotten, is no longer prepared, or is rememorized as a conventional cantrip.

The number of cantrips converted per this feat by a spellcaster cannot exceed either the number equal to the level number of the highest spell slot that the spellcaster has obtained, or the number of wizard  levels that the spellcaster has, which ever is larger.

During this conversion the cantrips may only be cast by expending a spell slot if available as one expends a spell slot when casting a level-one spell or higher.  The cantrip may not be cast otherwise until the spellcaster is allowed to change their list of known or prepared spells and prepare the spell in memory as a conventional cantrip. 

The spell caster may use this feat once when they gain the feat or anytime they are allowed to change their list of known or prepared spells. Only cantrips from the list of Wizard's spells may be converted using this feat.  If a spellcaster is limited in the number of spells that they can learn or switch per level, this feat does not increase this number. 

The action of converting a previously prepared  spell up to a level-one conversion or back down to conventional cantrip status is considered a free change to the spells list in lieu of other limitations.

The term "list prepared spells" refers to the rituals of preparation that a Wizard is described to do for a time before casting, where the term "list of known spells" refers the subclasses that may only learn and prepare new spells once per level.  This list includes, but is not limited to, the Eldritch Knight  and the Arcane Trickster.