To read again with fresh rules — parsing repeated because the first reading has been outgrown.
Re- (Latin, again) attached to parse, from Latin pars (orationis) (part of speech), a phrase used in teaching grammar, later verbed as to parse; to reparse is to name the parts again under rules that have since changed.
To read again with fresh rules. The root's naming-of-parts is repeated because the first reading has since been outgrown by what it needs to describe.