(a) After the filing of any accusation, an investigation shall be made and an attempt to eliminate such practice or discrimination shall be made as provided in section 402 of this title, unless such attempt has previously been made.
(b) In case of failure to eliminate such practice or discrimination, or in advance thereof, if in the judgment of the department, circumstances warrant, a written accusation, together with a copy of such complaint as the same may have been amended, shall be issued and served requiring the person, employer, or employment agency named in such accusation, hereinafter referred to as “respondent” to answer the charges of such accusation at a hearing.