Del. Code Ann. tit. 9, § 721
Whenever any member of the governing board of any park district shall:
said office may be declared vacant. Vacancies shall be declared, and may be filled by appointment by a majority of the remaining members of the board, and any person so appointed shall hold that person’s office until the next regular election for members of the board when a successor for the unexpired term shall be elected.
9 Del. C. 1953, § 721; 52 Del. Laws, c. 42; 70 Del. Laws, c. 186, § 1