This is a one-use only item, which you can buy at a rift shop for 5,000 rift crystals (single use). You can adjust everything including name, voice, looks, and build of your character and main pawn as if creating them for the first time.
Once you buy this item it will appear as a edit option at the title screen. When you agree with the changes you made the edit option will be removed from the title menu.
NOTE: If you select the edit option from the title screen and afterwards change your mind about editing you character and pawn and decide to exit the edit option, it is still considered a "use" and the edit option will be removed from the title screen upon exit. (Waste of Rift Crystals).