Single post in Deleting accounts
Forum Index > Core > Suggestions > Rejected > Deleting accounts >
You'd have to submit a ticket in the support centre, it's in Other Links on the Farm page.
As far as I'm aware tho, you're not allowed to create a second account even if you deactivate the first one. Closest you can get to a restart is use a BFM (on the bottom of the Pokedex page) and release all your Pokemon.