Del. Code tit. 30 § 523
Within 60 days (30 days in the case of withholding taxes or retail marijuana taxes, or, in the case of other taxes imposed by Chapter 11 of this title, 120 days if the taxpayer is outside the United States) after the date of the mailing of a notice of proposed assessment under § 521(c) of this title or the date of the mailing of a notice of the disallowance of a claim for credit or refund under § 542 of this title, the taxpayer may file with the Director a written protest against the proposed assessment or disallowance in which the taxpayer shall set forth the grounds upon which the protest is based. If such a protest is filed, the Director shall reconsider the proposed assessment or disallowance of claim for credit or refund and, if the taxpayer has so requested, shall grant the taxpayer or the taxpayer's authorized representative an oral hearing.
30 Del. C. § 523