Del. Code Ann. tit. 10, § 6504
Any person interested as or through an executor, administrator, trustee, guardian, fiduciary, adviser, or protector under § 3313(a) of Title 12, designated representative under § 3339 of Title 12, creditor, devisee, legatee, heir, next-of kin or cestui que trust, in the administration of a trust, or the administration of the estate of a decedent, an infant, or a person with a mental condition, may have a declaration of rights or legal relations in respect thereto:
63 Del. Laws, c. 63, § 1; 78 Del. Laws, c. 179, § 25; 81 Del. Laws, c. 320, § 2; 84 Del. Laws, c. 182, § 1