@ProfessorMilesXCan you use the Mend cantrip in reverse and break small mundane objects? I know earlier editions had such options. If the cantrip allowed you to break things, it would say so. It doesn't.
— Jeremy Crawford (@JeremyECrawford) March 23, 2017
Spells cannot be reversed unless stated in the text (I can’t think of any). Would be interesting if they could … Reverse fireball to extinguish fires; Any damage spell give healing instead; Reverse ‘Friend’ spell; etc.