By reset I mean the returning of the crystals you have earned so that you can respend them as different upgrades become available due to rank increase.

Heres an idea, how about a way to refund your crystals youve got so you can redistribute them accordingly as you rank up. Perhaps a sysytem like paying 1000 crystals to reset your crystals or something. I dont know, just saying it would be a cool feature for those of us who arnt loaded with cash to invest in this game :)