Transpose

Prerequisite The ability to cast spells

You have mastered an ancient art that allows you to increase the potency of your spell slots. If you focus your mind for 1 minute, you can expend a spell slot to regain an expended spell slot that is one level higher. The highest spell slot you can regain in this manner is 5th level.
You can do this a number of times equal to your spellcasting modifier. You regain all uses of this feature at the end of a long rest.