Answer: rectifying

AnswerCrossword Clue
rectifyingConvert (alternating current) to direct current
rectifyingPurify or refine (a substance), esp. by repeated distillation
rectifyingRECTIFY, to correct (to make right (in accordance with what is true and fitting))
rectifyingFind a straight line equal in length to (a curve)
rectifyingPut (something) right; correct