Haw. Rev. Stat. § 26-37: Substitutes for officials called into active service.

The head of any department or bureau of the State may employ such temporary assistants, subordinates, or employees as may be necessary in case any such head or any assistants, subordinates, or employees are called into active service as members of the armed forces of the United States or of the national guard.

Any appointment or employment so made shall be only after consultation by the head of the department or bureau with the governor and only with the approval of the governor.